Area units and conversion between metric and US (#123563)

* area conversions

* start work on tests

* add number device class

* update unit conversions to utilise distance constants

* add area unit

* update test unit system

* update device condition and trigger

* update statistic unit converters

* further tests work WIP

* update test unit system

* add missing string translations

* fix websocket tests

* add deprecated notice

* add more missing strings and missing initialisation of unit system

* adjust icon and remove strings from scrape and random

* Fix acre to meters conversion

Co-authored-by: epenet <6771947+epenet@users.noreply.github.com>

* Tidy up valid units

Co-authored-by: epenet <6771947+epenet@users.noreply.github.com>

* fix ordering of area

* update order alphabetically

* fix broken test

* update test_init

* Update homeassistant/const.py

Co-authored-by: epenet <6771947+epenet@users.noreply.github.com>

* remove deprecated unit and fix alphabetical order

* change deprecation and add tests, change to millimeter conversion for inches

* fix order

* re-order defs alphabetically

* add measurement as well

* update icons

* fix up Deprecation of area square meters

* Update core integrations to UnitOfArea

* update test recorder tests

* unit system tests in alphabetical

* update snapshot

* rebuild

* revert alphabetization of functions

* other revert of alphabetical order

---------

Co-authored-by: epenet <6771947+epenet@users.noreply.github.com>

homeassistant/components/ecovacs/sensor.py

@@ -26,11 +26,11 @@ from homeassistant.components.sensor import (
     SensorStateClass,
 )
 from homeassistant.const import (
-    AREA_SQUARE_METERS,
     ATTR_BATTERY_LEVEL,
     CONF_DESCRIPTION,
     PERCENTAGE,
     EntityCategory,
+    UnitOfArea,
     UnitOfTime,
 )
 from homeassistant.core import HomeAssistant
@@ -67,7 +67,7 @@ ENTITY_DESCRIPTIONS: tuple[EcovacsSensorEntityDescription, ...] = (
         capability_fn=lambda caps: caps.stats.clean,
         value_fn=lambda e: e.area,
         translation_key="stats_area",
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
     ),
     EcovacsSensorEntityDescription[StatsEvent](
         key="stats_time",
@@ -84,7 +84,7 @@ ENTITY_DESCRIPTIONS: tuple[EcovacsSensorEntityDescription, ...] = (
         value_fn=lambda e: e.area,
         key="total_stats_area",
         translation_key="total_stats_area",
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
         state_class=SensorStateClass.TOTAL_INCREASING,
     ),
     EcovacsSensorEntityDescription[TotalStatsEvent](

homeassistant/components/number/const.py

@@ -17,6 +17,7 @@ from homeassistant.const import (
     SIGNAL_STRENGTH_DECIBELS,
     SIGNAL_STRENGTH_DECIBELS_MILLIWATT,
     UnitOfApparentPower,
+    UnitOfArea,
     UnitOfBloodGlucoseConcentration,
     UnitOfConductivity,
     UnitOfDataRate,
@@ -98,6 +99,12 @@ class NumberDeviceClass(StrEnum):
     Unit of measurement: `None`
     """
 
+    AREA = "area"
+    """Area
+
+    Unit of measurement: `UnitOfArea` units
+    """
+
     ATMOSPHERIC_PRESSURE = "atmospheric_pressure"
     """Atmospheric pressure.
 
@@ -434,6 +441,7 @@ DEVICE_CLASSES_SCHEMA: Final = vol.All(vol.Lower, vol.Coerce(NumberDeviceClass))
 DEVICE_CLASS_UNITS: dict[NumberDeviceClass, set[type[StrEnum] | str | None]] = {
     NumberDeviceClass.APPARENT_POWER: set(UnitOfApparentPower),
     NumberDeviceClass.AQI: {None},
+    NumberDeviceClass.AREA: set(UnitOfArea),
     NumberDeviceClass.ATMOSPHERIC_PRESSURE: set(UnitOfPressure),
     NumberDeviceClass.BATTERY: {PERCENTAGE},
     NumberDeviceClass.BLOOD_GLUCOSE_CONCENTRATION: set(UnitOfBloodGlucoseConcentration),

homeassistant/components/number/icons.json

@@ -9,6 +9,9 @@
     "aqi": {
       "default": "mdi:air-filter"
     },
+    "area": {
+      "default": "mdi:texture-box"
+    },
     "atmospheric_pressure": {
       "default": "mdi:thermometer-lines"
     },

homeassistant/components/number/strings.json

@@ -37,6 +37,9 @@
     "aqi": {
       "name": "[%key:component::sensor::entity_component::aqi::name%]"
     },
+    "area": {
+      "name": "[%key:component::sensor::entity_component::area::name%]"
+    },
     "atmospheric_pressure": {
       "name": "[%key:component::sensor::entity_component::atmospheric_pressure::name%]"
     },

homeassistant/components/recorder/statistics.py

@@ -27,6 +27,7 @@ from homeassistant.helpers.singleton import singleton
 from homeassistant.helpers.typing import UNDEFINED, UndefinedType
 from homeassistant.util import dt as dt_util
 from homeassistant.util.unit_conversion import (
+    AreaConverter,
     BaseUnitConverter,
     BloodGlucoseConcentrationConverter,
     ConductivityConverter,
@@ -129,6 +130,7 @@ QUERY_STATISTICS_SUMMARY_SUM = (
 
 
 STATISTIC_UNIT_TO_UNIT_CONVERTER: dict[str | None, type[BaseUnitConverter]] = {
+    **{unit: AreaConverter for unit in AreaConverter.VALID_UNITS},
     **{
         unit: BloodGlucoseConcentrationConverter
         for unit in BloodGlucoseConcentrationConverter.VALID_UNITS

homeassistant/components/recorder/websocket_api.py

@@ -16,6 +16,7 @@ from homeassistant.helpers import config_validation as cv
 from homeassistant.helpers.json import json_bytes
 from homeassistant.util import dt as dt_util
 from homeassistant.util.unit_conversion import (
+    AreaConverter,
     BloodGlucoseConcentrationConverter,
     ConductivityConverter,
     DataRateConverter,
@@ -55,6 +56,7 @@ UPDATE_STATISTICS_METADATA_TIME_OUT = 10
 
 UNIT_SCHEMA = vol.Schema(
     {
+        vol.Optional("area"): vol.In(AreaConverter.VALID_UNITS),
         vol.Optional("blood_glucose_concentration"): vol.In(
             BloodGlucoseConcentrationConverter.VALID_UNITS
         ),

homeassistant/components/rituals_perfume_genie/select.py

@@ -9,7 +9,7 @@ from pyrituals import Diffuser
 
 from homeassistant.components.select import SelectEntity, SelectEntityDescription
 from homeassistant.config_entries import ConfigEntry
-from homeassistant.const import AREA_SQUARE_METERS, EntityCategory
+from homeassistant.const import EntityCategory, UnitOfArea
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 
@@ -30,7 +30,7 @@ ENTITY_DESCRIPTIONS = (
     RitualsSelectEntityDescription(
         key="room_size_square_meter",
         translation_key="room_size_square_meter",
-        unit_of_measurement=AREA_SQUARE_METERS,
+        unit_of_measurement=UnitOfArea.SQUARE_METERS,
         entity_category=EntityCategory.CONFIG,
         options=["15", "30", "60", "100"],
         current_fn=lambda diffuser: str(diffuser.room_size_square_meter),

homeassistant/components/roborock/sensor.py

@@ -25,12 +25,7 @@ from homeassistant.components.sensor import (
     SensorEntity,
     SensorEntityDescription,
 )
-from homeassistant.const import (
+from homeassistant.const import PERCENTAGE, EntityCategory, UnitOfArea, UnitOfTime
-    AREA_SQUARE_METERS,
-    PERCENTAGE,
-    EntityCategory,
-    UnitOfTime,
-)
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.typing import StateType
@@ -131,14 +126,14 @@ SENSOR_DESCRIPTIONS = [
         translation_key="cleaning_area",
         value_fn=lambda data: data.status.square_meter_clean_area,
         entity_category=EntityCategory.DIAGNOSTIC,
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
     ),
     RoborockSensorDescription(
         key="total_cleaning_area",
         translation_key="total_cleaning_area",
         value_fn=lambda data: data.clean_summary.square_meter_clean_area,
         entity_category=EntityCategory.DIAGNOSTIC,
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
     ),
     RoborockSensorDescription(
         key="vacuum_error",

homeassistant/components/romy/sensor.py

@@ -8,10 +8,10 @@ from homeassistant.components.sensor import (
 )
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
-    AREA_SQUARE_METERS,
     PERCENTAGE,
     SIGNAL_STRENGTH_DECIBELS_MILLIWATT,
     EntityCategory,
+    UnitOfArea,
     UnitOfLength,
     UnitOfTime,
 )
@@ -61,7 +61,7 @@ SENSORS: list[SensorEntityDescription] = [
         key="total_area_cleaned",
         translation_key="total_area_cleaned",
         state_class=SensorStateClass.TOTAL,
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
         entity_category=EntityCategory.DIAGNOSTIC,
     ),
     SensorEntityDescription(

homeassistant/components/roomba/sensor.py

@@ -12,12 +12,7 @@ from homeassistant.components.sensor import (
     SensorStateClass,
 )
 from homeassistant.config_entries import ConfigEntry
-from homeassistant.const import (
+from homeassistant.const import PERCENTAGE, EntityCategory, UnitOfArea, UnitOfTime
-    AREA_SQUARE_METERS,
-    PERCENTAGE,
-    EntityCategory,
-    UnitOfTime,
-)
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.typing import StateType
@@ -108,7 +103,7 @@ SENSORS: list[RoombaSensorEntityDescription] = [
     RoombaSensorEntityDescription(
         key="total_cleaned_area",
         translation_key="total_cleaned_area",
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
         entity_category=EntityCategory.DIAGNOSTIC,
         value_fn=lambda self: (
             None if (sqft := self.run_stats.get("sqft")) is None else sqft * 9.29

homeassistant/components/sensor/const.py

@@ -17,6 +17,7 @@ from homeassistant.const import (
     SIGNAL_STRENGTH_DECIBELS,
     SIGNAL_STRENGTH_DECIBELS_MILLIWATT,
     UnitOfApparentPower,
+    UnitOfArea,
     UnitOfBloodGlucoseConcentration,
     UnitOfConductivity,
     UnitOfDataRate,
@@ -47,6 +48,7 @@ from homeassistant.helpers.deprecation import (
     dir_with_deprecated_constants,
 )
 from homeassistant.util.unit_conversion import (
+    AreaConverter,
     BaseUnitConverter,
     BloodGlucoseConcentrationConverter,
     ConductivityConverter,
@@ -117,6 +119,12 @@ class SensorDeviceClass(StrEnum):
     Unit of measurement: `None`
     """
 
+    AREA = "area"
+    """Area
+
+    Unit of measurement: `UnitOfArea` units
+    """
+
     ATMOSPHERIC_PRESSURE = "atmospheric_pressure"
     """Atmospheric pressure.
 
@@ -500,6 +508,7 @@ _DEPRECATED_STATE_CLASS_TOTAL_INCREASING: Final = DeprecatedConstantEnum(
 STATE_CLASSES: Final[list[str]] = [cls.value for cls in SensorStateClass]
 
 UNIT_CONVERTERS: dict[SensorDeviceClass | str | None, type[BaseUnitConverter]] = {
+    SensorDeviceClass.AREA: AreaConverter,
     SensorDeviceClass.ATMOSPHERIC_PRESSURE: PressureConverter,
     SensorDeviceClass.BLOOD_GLUCOSE_CONCENTRATION: BloodGlucoseConcentrationConverter,
     SensorDeviceClass.CONDUCTIVITY: ConductivityConverter,
@@ -531,6 +540,7 @@ UNIT_CONVERTERS: dict[SensorDeviceClass | str | None, type[BaseUnitConverter]] =
 DEVICE_CLASS_UNITS: dict[SensorDeviceClass, set[type[StrEnum] | str | None]] = {
     SensorDeviceClass.APPARENT_POWER: set(UnitOfApparentPower),
     SensorDeviceClass.AQI: {None},
+    SensorDeviceClass.AREA: set(UnitOfArea),
     SensorDeviceClass.ATMOSPHERIC_PRESSURE: set(UnitOfPressure),
     SensorDeviceClass.BATTERY: {PERCENTAGE},
     SensorDeviceClass.BLOOD_GLUCOSE_CONCENTRATION: set(UnitOfBloodGlucoseConcentration),
@@ -607,6 +617,7 @@ DEVICE_CLASS_UNITS: dict[SensorDeviceClass, set[type[StrEnum] | str | None]] = {
 DEVICE_CLASS_STATE_CLASSES: dict[SensorDeviceClass, set[SensorStateClass]] = {
     SensorDeviceClass.APPARENT_POWER: {SensorStateClass.MEASUREMENT},
     SensorDeviceClass.AQI: {SensorStateClass.MEASUREMENT},
+    SensorDeviceClass.AREA: set(SensorStateClass),
     SensorDeviceClass.ATMOSPHERIC_PRESSURE: {SensorStateClass.MEASUREMENT},
     SensorDeviceClass.BATTERY: {SensorStateClass.MEASUREMENT},
     SensorDeviceClass.BLOOD_GLUCOSE_CONCENTRATION: {SensorStateClass.MEASUREMENT},

homeassistant/components/sensor/device_condition.py

@@ -35,6 +35,7 @@ DEVICE_CLASS_NONE = "none"
 
 CONF_IS_APPARENT_POWER = "is_apparent_power"
 CONF_IS_AQI = "is_aqi"
+CONF_IS_AREA = "is_area"
 CONF_IS_ATMOSPHERIC_PRESSURE = "is_atmospheric_pressure"
 CONF_IS_BATTERY_LEVEL = "is_battery_level"
 CONF_IS_BLOOD_GLUCOSE_CONCENTRATION = "is_blood_glucose_concentration"
@@ -86,6 +87,7 @@ CONF_IS_WIND_SPEED = "is_wind_speed"
 ENTITY_CONDITIONS = {
     SensorDeviceClass.APPARENT_POWER: [{CONF_TYPE: CONF_IS_APPARENT_POWER}],
     SensorDeviceClass.AQI: [{CONF_TYPE: CONF_IS_AQI}],
+    SensorDeviceClass.AREA: [{CONF_TYPE: CONF_IS_AREA}],
     SensorDeviceClass.ATMOSPHERIC_PRESSURE: [{CONF_TYPE: CONF_IS_ATMOSPHERIC_PRESSURE}],
     SensorDeviceClass.BATTERY: [{CONF_TYPE: CONF_IS_BATTERY_LEVEL}],
     SensorDeviceClass.BLOOD_GLUCOSE_CONCENTRATION: [
@@ -153,6 +155,7 @@ CONDITION_SCHEMA = vol.All(
                 [
                     CONF_IS_APPARENT_POWER,
                     CONF_IS_AQI,
+                    CONF_IS_AREA,
                     CONF_IS_ATMOSPHERIC_PRESSURE,
                     CONF_IS_BATTERY_LEVEL,
                     CONF_IS_BLOOD_GLUCOSE_CONCENTRATION,

homeassistant/components/sensor/device_trigger.py

@@ -34,6 +34,7 @@ DEVICE_CLASS_NONE = "none"
 
 CONF_APPARENT_POWER = "apparent_power"
 CONF_AQI = "aqi"
+CONF_AREA = "area"
 CONF_ATMOSPHERIC_PRESSURE = "atmospheric_pressure"
 CONF_BATTERY_LEVEL = "battery_level"
 CONF_BLOOD_GLUCOSE_CONCENTRATION = "blood_glucose_concentration"
@@ -85,6 +86,7 @@ CONF_WIND_SPEED = "wind_speed"
 ENTITY_TRIGGERS = {
     SensorDeviceClass.APPARENT_POWER: [{CONF_TYPE: CONF_APPARENT_POWER}],
     SensorDeviceClass.AQI: [{CONF_TYPE: CONF_AQI}],
+    SensorDeviceClass.AREA: [{CONF_TYPE: CONF_AREA}],
     SensorDeviceClass.ATMOSPHERIC_PRESSURE: [{CONF_TYPE: CONF_ATMOSPHERIC_PRESSURE}],
     SensorDeviceClass.BATTERY: [{CONF_TYPE: CONF_BATTERY_LEVEL}],
     SensorDeviceClass.BLOOD_GLUCOSE_CONCENTRATION: [
@@ -153,6 +155,7 @@ TRIGGER_SCHEMA = vol.All(
                 [
                     CONF_APPARENT_POWER,
                     CONF_AQI,
+                    CONF_AREA,
                     CONF_ATMOSPHERIC_PRESSURE,
                     CONF_BATTERY_LEVEL,
                     CONF_BLOOD_GLUCOSE_CONCENTRATION,

homeassistant/components/sensor/icons.json

@@ -9,6 +9,9 @@
     "aqi": {
       "default": "mdi:air-filter"
     },
+    "area": {
+      "default": "mdi:texture-box"
+    },
     "atmospheric_pressure": {
       "default": "mdi:thermometer-lines"
     },

homeassistant/components/sensor/strings.json

@@ -4,6 +4,7 @@
     "condition_type": {
       "is_apparent_power": "Current {entity_name} apparent power",
       "is_aqi": "Current {entity_name} air quality index",
+      "is_area": "Current {entity_name} area",
       "is_atmospheric_pressure": "Current {entity_name} atmospheric pressure",
       "is_battery_level": "Current {entity_name} battery level",
       "is_blood_glucose_concentration": "Current {entity_name} blood glucose concentration",
@@ -55,6 +56,7 @@
     "trigger_type": {
       "apparent_power": "{entity_name} apparent power changes",
       "aqi": "{entity_name} air quality index changes",
+      "area": "{entity_name} area changes",
       "atmospheric_pressure": "{entity_name} atmospheric pressure changes",
       "battery_level": "{entity_name} battery level changes",
       "blood_glucose_concentration": "{entity_name} blood glucose concentration changes",
@@ -145,6 +147,9 @@
     "aqi": {
       "name": "Air quality index"
     },
+    "area": {
+      "name": "Area"
+    },
     "atmospheric_pressure": {
       "name": "Atmospheric pressure"
     },

homeassistant/components/smartthings/sensor.py

@@ -15,11 +15,11 @@ from homeassistant.components.sensor import (
 )
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
-    AREA_SQUARE_METERS,
     CONCENTRATION_PARTS_PER_MILLION,
     LIGHT_LUX,
     PERCENTAGE,
     EntityCategory,
+    UnitOfArea,
     UnitOfElectricPotential,
     UnitOfEnergy,
     UnitOfMass,
@@ -95,7 +95,7 @@ CAPABILITY_TO_SENSORS: dict[str, list[Map]] = {
         Map(
             Attribute.bmi_measurement,
             "Body Mass Index",
-            f"{UnitOfMass.KILOGRAMS}/{AREA_SQUARE_METERS}",
+            f"{UnitOfMass.KILOGRAMS}/{UnitOfArea.SQUARE_METERS}",
             None,
             SensorStateClass.MEASUREMENT,
             None,

homeassistant/components/xiaomi_miio/sensor.py

@@ -24,7 +24,6 @@ from homeassistant.components.sensor import (
 )
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
-    AREA_SQUARE_METERS,
     ATTR_BATTERY_LEVEL,
     ATTR_TEMPERATURE,
     CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
@@ -37,6 +36,7 @@ from homeassistant.const import (
     PERCENTAGE,
     REVOLUTIONS_PER_MINUTE,
     EntityCategory,
+    UnitOfArea,
     UnitOfPower,
     UnitOfPressure,
     UnitOfTemperature,
@@ -622,7 +622,7 @@ VACUUM_SENSORS = {
         entity_category=EntityCategory.DIAGNOSTIC,
     ),
     f"last_clean_{ATTR_LAST_CLEAN_AREA}": XiaomiMiioSensorDescription(
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
         icon="mdi:texture-box",
         key=ATTR_LAST_CLEAN_AREA,
         parent_key=VacuumCoordinatorDataAttributes.last_clean_details,
@@ -639,7 +639,7 @@ VACUUM_SENSORS = {
         entity_category=EntityCategory.DIAGNOSTIC,
     ),
     f"current_{ATTR_LAST_CLEAN_AREA}": XiaomiMiioSensorDescription(
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
         icon="mdi:texture-box",
         key=ATTR_STATUS_CLEAN_AREA,
         parent_key=VacuumCoordinatorDataAttributes.status,
@@ -657,7 +657,7 @@ VACUUM_SENSORS = {
         entity_category=EntityCategory.DIAGNOSTIC,
     ),
     f"clean_history_{ATTR_CLEAN_HISTORY_TOTAL_AREA}": XiaomiMiioSensorDescription(
-        native_unit_of_measurement=AREA_SQUARE_METERS,
+        native_unit_of_measurement=UnitOfArea.SQUARE_METERS,
         icon="mdi:texture-box",
         key=ATTR_CLEAN_HISTORY_TOTAL_AREA,
         parent_key=VacuumCoordinatorDataAttributes.clean_history_status,

homeassistant/const.py

@@ -1179,8 +1179,27 @@ _DEPRECATED_VOLUME_FLOW_RATE_CUBIC_FEET_PER_MINUTE: Final = DeprecatedConstantEn
 )
 """Deprecated: please use UnitOfVolumeFlowRate.CUBIC_FEET_PER_MINUTE"""
 
-# Area units
+
-AREA_SQUARE_METERS: Final = "m²"
+class UnitOfArea(StrEnum):
+    """Area units."""
+
+    SQUARE_METERS = "m²"
+    SQUARE_CENTIMETERS = "cm²"
+    SQUARE_KILOMETERS = "km²"
+    SQUARE_MILLIMETERS = "mm²"
+    SQUARE_INCHES = "in²"
+    SQUARE_FEET = "ft²"
+    SQUARE_YARDS = "yd²"
+    SQUARE_MILES = "mi²"
+    ACRES = "ac"
+    HECTARES = "ha"
+
+
+_DEPRECATED_AREA_SQUARE_METERS: Final = DeprecatedConstantEnum(
+    UnitOfArea.SQUARE_METERS,
+    "2025.12",
+)
+"""Deprecated: please use UnitOfArea.SQUARE_METERS"""
 
 
 # Mass units
@@ -1704,6 +1723,7 @@ RESTART_EXIT_CODE: Final = 100
 UNIT_NOT_RECOGNIZED_TEMPLATE: Final = "{} is not a recognized {} unit."
 
 LENGTH: Final = "length"
+AREA: Final = "area"
 MASS: Final = "mass"
 PRESSURE: Final = "pressure"
 VOLUME: Final = "volume"

homeassistant/util/unit_conversion.py

@@ -10,6 +10,7 @@ from homeassistant.const import (
     CONCENTRATION_PARTS_PER_MILLION,
     PERCENTAGE,
     UNIT_NOT_RECOGNIZED_TEMPLATE,
+    UnitOfArea,
     UnitOfBloodGlucoseConcentration,
     UnitOfConductivity,
     UnitOfDataRate,
@@ -42,6 +43,19 @@ _MILE_TO_M = _YARD_TO_M * 1760  # 1760 yard = 1 mile (1609.344 m)
 
 _NAUTICAL_MILE_TO_M = 1852  # 1 nautical mile = 1852 m
 
+# Area constants to square meters
+_CM2_TO_M2 = _CM_TO_M**2  # 1 cm² = 0.0001 m²
+_MM2_TO_M2 = _MM_TO_M**2  # 1 mm² = 0.000001 m²
+_KM2_TO_M2 = _KM_TO_M**2  # 1 km² = 1,000,000 m²
+
+_IN2_TO_M2 = _IN_TO_M**2  # 1 in² = 0.00064516 m²
+_FT2_TO_M2 = _FOOT_TO_M**2  # 1 ft² = 0.092903 m²
+_YD2_TO_M2 = _YARD_TO_M**2  # 1 yd² = 0.836127 m²
+_MI2_TO_M2 = _MILE_TO_M**2  # 1 mi² = 2,590,000 m²
+
+_ACRE_TO_M2 = 66 * 660 * _FT2_TO_M2  # 1 acre = 4,046.86 m²
+_HECTARE_TO_M2 = 100 * 100  # 1 hectare = 10,000 m²
+
 # Duration conversion constants
 _MIN_TO_SEC = 60  # 1 min = 60 seconds
 _HRS_TO_MINUTES = 60  # 1 hr = 60 minutes
@@ -146,6 +160,25 @@ class DataRateConverter(BaseUnitConverter):
     VALID_UNITS = set(UnitOfDataRate)
 
 
+class AreaConverter(BaseUnitConverter):
+    """Utility to convert area values."""
+
+    UNIT_CLASS = "area"
+    _UNIT_CONVERSION: dict[str | None, float] = {
+        UnitOfArea.SQUARE_METERS: 1,
+        UnitOfArea.SQUARE_CENTIMETERS: 1 / _CM2_TO_M2,
+        UnitOfArea.SQUARE_MILLIMETERS: 1 / _MM2_TO_M2,
+        UnitOfArea.SQUARE_KILOMETERS: 1 / _KM2_TO_M2,
+        UnitOfArea.SQUARE_INCHES: 1 / _IN2_TO_M2,
+        UnitOfArea.SQUARE_FEET: 1 / _FT2_TO_M2,
+        UnitOfArea.SQUARE_YARDS: 1 / _YD2_TO_M2,
+        UnitOfArea.SQUARE_MILES: 1 / _MI2_TO_M2,
+        UnitOfArea.ACRES: 1 / _ACRE_TO_M2,
+        UnitOfArea.HECTARES: 1 / _HECTARE_TO_M2,
+    }
+    VALID_UNITS = set(UnitOfArea)
+
+
 class DistanceConverter(BaseUnitConverter):
     """Utility to convert distance values."""
 

homeassistant/util/unit_system.py

@@ -9,6 +9,7 @@ import voluptuous as vol
 
 from homeassistant.const import (
     ACCUMULATED_PRECIPITATION,
+    AREA,
     LENGTH,
     MASS,
     PRESSURE,
@@ -16,6 +17,7 @@ from homeassistant.const import (
     UNIT_NOT_RECOGNIZED_TEMPLATE,
     VOLUME,
     WIND_SPEED,
+    UnitOfArea,
     UnitOfLength,
     UnitOfMass,
     UnitOfPrecipitationDepth,
@@ -27,6 +29,7 @@ from homeassistant.const import (
 )
 
 from .unit_conversion import (
+    AreaConverter,
     DistanceConverter,
     PressureConverter,
     SpeedConverter,
@@ -41,6 +44,8 @@ _CONF_UNIT_SYSTEM_IMPERIAL: Final = "imperial"
 _CONF_UNIT_SYSTEM_METRIC: Final = "metric"
 _CONF_UNIT_SYSTEM_US_CUSTOMARY: Final = "us_customary"
 
+AREA_UNITS = AreaConverter.VALID_UNITS
+
 LENGTH_UNITS = DistanceConverter.VALID_UNITS
 
 MASS_UNITS: set[str] = {
@@ -66,6 +71,7 @@ _VALID_BY_TYPE: dict[str, set[str] | set[str | None]] = {
     MASS: MASS_UNITS,
     VOLUME: VOLUME_UNITS,
     PRESSURE: PRESSURE_UNITS,
+    AREA: AREA_UNITS,
 }
 
 
@@ -84,6 +90,7 @@ class UnitSystem:
         name: str,
         *,
         accumulated_precipitation: UnitOfPrecipitationDepth,
+        area: UnitOfArea,
         conversions: dict[tuple[SensorDeviceClass | str | None, str | None], str],
         length: UnitOfLength,
         mass: UnitOfMass,
@@ -97,6 +104,7 @@ class UnitSystem:
             UNIT_NOT_RECOGNIZED_TEMPLATE.format(unit, unit_type)
             for unit, unit_type in (
                 (accumulated_precipitation, ACCUMULATED_PRECIPITATION),
+                (area, AREA),
                 (temperature, TEMPERATURE),
                 (length, LENGTH),
                 (wind_speed, WIND_SPEED),
@@ -112,10 +120,11 @@ class UnitSystem:
 
         self._name = name
         self.accumulated_precipitation_unit = accumulated_precipitation
-        self.temperature_unit = temperature
+        self.area_unit = area
         self.length_unit = length
         self.mass_unit = mass
         self.pressure_unit = pressure
+        self.temperature_unit = temperature
         self.volume_unit = volume
         self.wind_speed_unit = wind_speed
         self._conversions = conversions
@@ -149,6 +158,16 @@ class UnitSystem:
             precip, from_unit, self.accumulated_precipitation_unit
         )
 
+    def area(self, area: float | None, from_unit: str) -> float:
+        """Convert the given area to this unit system."""
+        if not isinstance(area, Number):
+            raise TypeError(f"{area!s} is not a numeric value.")
+
+        # type ignore: https://github.com/python/mypy/issues/7207
+        return AreaConverter.convert(  # type: ignore[unreachable]
+            area, from_unit, self.area_unit
+        )
+
     def pressure(self, pressure: float | None, from_unit: str) -> float:
         """Convert the given pressure to this unit system."""
         if not isinstance(pressure, Number):
@@ -184,6 +203,7 @@ class UnitSystem:
         return {
             LENGTH: self.length_unit,
             ACCUMULATED_PRECIPITATION: self.accumulated_precipitation_unit,
+            AREA: self.area_unit,
             MASS: self.mass_unit,
             PRESSURE: self.pressure_unit,
             TEMPERATURE: self.temperature_unit,
@@ -234,6 +254,12 @@ METRIC_SYSTEM = UnitSystem(
             for unit in UnitOfPressure
             if unit != UnitOfPressure.HPA
         },
+        # Convert non-metric area
+        ("area", UnitOfArea.SQUARE_INCHES): UnitOfArea.SQUARE_CENTIMETERS,
+        ("area", UnitOfArea.SQUARE_FEET): UnitOfArea.SQUARE_METERS,
+        ("area", UnitOfArea.SQUARE_MILES): UnitOfArea.SQUARE_KILOMETERS,
+        ("area", UnitOfArea.SQUARE_YARDS): UnitOfArea.SQUARE_METERS,
+        ("area", UnitOfArea.ACRES): UnitOfArea.HECTARES,
         # Convert non-metric distances
         ("distance", UnitOfLength.FEET): UnitOfLength.METERS,
         ("distance", UnitOfLength.INCHES): UnitOfLength.MILLIMETERS,
@@ -285,6 +311,7 @@ METRIC_SYSTEM = UnitSystem(
             if unit not in (UnitOfSpeed.KILOMETERS_PER_HOUR, UnitOfSpeed.KNOTS)
         },
     },
+    area=UnitOfArea.SQUARE_METERS,
     length=UnitOfLength.KILOMETERS,
     mass=UnitOfMass.GRAMS,
     pressure=UnitOfPressure.PA,
@@ -303,6 +330,12 @@ US_CUSTOMARY_SYSTEM = UnitSystem(
             for unit in UnitOfPressure
             if unit != UnitOfPressure.INHG
         },
+        # Convert non-USCS areas
+        ("area", UnitOfArea.SQUARE_METERS): UnitOfArea.SQUARE_FEET,
+        ("area", UnitOfArea.SQUARE_CENTIMETERS): UnitOfArea.SQUARE_INCHES,
+        ("area", UnitOfArea.SQUARE_MILLIMETERS): UnitOfArea.SQUARE_INCHES,
+        ("area", UnitOfArea.SQUARE_KILOMETERS): UnitOfArea.SQUARE_MILES,
+        ("area", UnitOfArea.HECTARES): UnitOfArea.ACRES,
         # Convert non-USCS distances
         ("distance", UnitOfLength.CENTIMETERS): UnitOfLength.INCHES,
         ("distance", UnitOfLength.KILOMETERS): UnitOfLength.MILES,
@@ -356,6 +389,7 @@ US_CUSTOMARY_SYSTEM = UnitSystem(
             if unit not in (UnitOfSpeed.KNOTS, UnitOfSpeed.MILES_PER_HOUR)
         },
     },
+    area=UnitOfArea.SQUARE_FEET,
     length=UnitOfLength.MILES,
     mass=UnitOfMass.POUNDS,
     pressure=UnitOfPressure.PSI,

tests/components/ecovacs/snapshots/test_sensor.ambr

@@ -177,14 +177,14 @@
     'supported_features': 0,
     'translation_key': 'stats_area',
     'unique_id': '8516fbb1-17f1-4194-0000000_stats_area',
-    'unit_of_measurement': 'm²',
+    'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
   })
 # ---
 # name: test_sensors[5xu9h3][sensor.goat_g1_area_cleaned:state]
   StateSnapshot({
     'attributes': ReadOnlyDict({
       'friendly_name': 'Goat G1 Area cleaned',
-      'unit_of_measurement': 'm²',
+      'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
     }),
     'context': <ANY>,
     'entity_id': 'sensor.goat_g1_area_cleaned',
@@ -512,7 +512,7 @@
     'supported_features': 0,
     'translation_key': 'total_stats_area',
     'unique_id': '8516fbb1-17f1-4194-0000000_total_stats_area',
-    'unit_of_measurement': 'm²',
+    'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
   })
 # ---
 # name: test_sensors[5xu9h3][sensor.goat_g1_total_area_cleaned:state]
@@ -520,7 +520,7 @@
     'attributes': ReadOnlyDict({
       'friendly_name': 'Goat G1 Total area cleaned',
       'state_class': <SensorStateClass.TOTAL_INCREASING: 'total_increasing'>,
-      'unit_of_measurement': 'm²',
+      'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
     }),
     'context': <ANY>,
     'entity_id': 'sensor.goat_g1_total_area_cleaned',
@@ -755,14 +755,14 @@
     'supported_features': 0,
     'translation_key': 'stats_area',
     'unique_id': 'E1234567890000000001_stats_area',
-    'unit_of_measurement': 'm²',
+    'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
   })
 # ---
 # name: test_sensors[yna5x1][sensor.ozmo_950_area_cleaned:state]
   StateSnapshot({
     'attributes': ReadOnlyDict({
       'friendly_name': 'Ozmo 950 Area cleaned',
-      'unit_of_measurement': 'm²',
+      'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
     }),
     'context': <ANY>,
     'entity_id': 'sensor.ozmo_950_area_cleaned',
@@ -1137,7 +1137,7 @@
     'supported_features': 0,
     'translation_key': 'total_stats_area',
     'unique_id': 'E1234567890000000001_total_stats_area',
-    'unit_of_measurement': 'm²',
+    'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
   })
 # ---
 # name: test_sensors[yna5x1][sensor.ozmo_950_total_area_cleaned:state]
@@ -1145,7 +1145,7 @@
     'attributes': ReadOnlyDict({
       'friendly_name': 'Ozmo 950 Total area cleaned',
       'state_class': <SensorStateClass.TOTAL_INCREASING: 'total_increasing'>,
-      'unit_of_measurement': 'm²',
+      'unit_of_measurement': <UnitOfArea.SQUARE_METERS: 'm²'>,
     }),
     'context': <ANY>,
     'entity_id': 'sensor.ozmo_950_total_area_cleaned',

tests/components/recorder/test_websocket_api.py

@@ -51,6 +51,16 @@ async def mock_recorder_before_hass(
     """Set up recorder."""
 
 
+AREA_SENSOR_FT_ATTRIBUTES = {
+    "device_class": "area",
+    "state_class": "measurement",
+    "unit_of_measurement": "ft²",
+}
+AREA_SENSOR_M_ATTRIBUTES = {
+    "device_class": "area",
+    "state_class": "measurement",
+    "unit_of_measurement": "m²",
+}
 DISTANCE_SENSOR_FT_ATTRIBUTES = {
     "device_class": "distance",
     "state_class": "measurement",
@@ -1247,6 +1257,9 @@ async def test_statistic_during_period_calendar(
 @pytest.mark.parametrize(
     ("attributes", "state", "value", "custom_units", "converted_value"),
     [
+        (AREA_SENSOR_M_ATTRIBUTES, 10, 10, {"area": "cm²"}, 100000),
+        (AREA_SENSOR_M_ATTRIBUTES, 10, 10, {"area": "m²"}, 10),
+        (AREA_SENSOR_M_ATTRIBUTES, 10, 10, {"area": "ft²"}, 107.639),
         (DISTANCE_SENSOR_M_ATTRIBUTES, 10, 10, {"distance": "cm"}, 1000),
         (DISTANCE_SENSOR_M_ATTRIBUTES, 10, 10, {"distance": "m"}, 10),
         (DISTANCE_SENSOR_M_ATTRIBUTES, 10, 10, {"distance": "in"}, 10 / 0.0254),
@@ -1434,6 +1447,7 @@ async def test_sum_statistics_during_period_unit_conversion(
     "custom_units",
     [
         {"distance": "L"},
+        {"area": "L"},
         {"energy": "W"},
         {"power": "Pa"},
         {"pressure": "K"},
@@ -1678,6 +1692,8 @@ async def test_statistics_during_period_empty_statistic_ids(
 @pytest.mark.parametrize(
     ("units", "attributes", "display_unit", "statistics_unit", "unit_class"),
     [
+        (US_CUSTOMARY_SYSTEM, AREA_SENSOR_M_ATTRIBUTES, "m²", "m²", "area"),
+        (METRIC_SYSTEM, AREA_SENSOR_M_ATTRIBUTES, "m²", "m²", "area"),
         (US_CUSTOMARY_SYSTEM, DISTANCE_SENSOR_M_ATTRIBUTES, "m", "m", "distance"),
         (METRIC_SYSTEM, DISTANCE_SENSOR_M_ATTRIBUTES, "m", "m", "distance"),
         (
@@ -1852,6 +1868,13 @@ async def test_list_statistic_ids(
 @pytest.mark.parametrize(
     ("attributes", "attributes2", "display_unit", "statistics_unit", "unit_class"),
     [
+        (
+            AREA_SENSOR_M_ATTRIBUTES,
+            AREA_SENSOR_FT_ATTRIBUTES,
+            "ft²",
+            "m²",
+            "area",
+        ),
         (
             DISTANCE_SENSOR_M_ATTRIBUTES,
             DISTANCE_SENSOR_FT_ATTRIBUTES,

tests/components/rituals_perfume_genie/test_select.py

@@ -9,10 +9,10 @@ from homeassistant.components.select import (
     DOMAIN as SELECT_DOMAIN,
 )
 from homeassistant.const import (
-    AREA_SQUARE_METERS,
     ATTR_ENTITY_ID,
     SERVICE_SELECT_OPTION,
     EntityCategory,
+    UnitOfArea,
 )
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import ServiceValidationError
@@ -38,7 +38,7 @@ async def test_select_entity(
     entry = entity_registry.async_get("select.genie_room_size")
     assert entry
     assert entry.unique_id == f"{diffuser.hublot}-room_size_square_meter"
-    assert entry.unit_of_measurement == AREA_SQUARE_METERS
+    assert entry.unit_of_measurement == UnitOfArea.SQUARE_METERS
     assert entry.entity_category == EntityCategory.CONFIG
 
 

tests/components/sensor/test_init.py

@@ -30,6 +30,7 @@ from homeassistant.const import (
     PERCENTAGE,
     STATE_UNKNOWN,
     EntityCategory,
+    UnitOfArea,
     UnitOfDataRate,
     UnitOfEnergy,
     UnitOfLength,
@@ -651,6 +652,34 @@ async def test_custom_unit(
         "device_class",
     ),
     [
+        # Area
+        (
+            UnitOfArea.SQUARE_KILOMETERS,
+            UnitOfArea.SQUARE_MILES,
+            UnitOfArea.SQUARE_MILES,
+            1000,
+            "1000",
+            "386",
+            SensorDeviceClass.AREA,
+        ),
+        (
+            UnitOfArea.SQUARE_CENTIMETERS,
+            UnitOfArea.SQUARE_INCHES,
+            UnitOfArea.SQUARE_INCHES,
+            7.24,
+            "7.24",
+            "1.12",
+            SensorDeviceClass.AREA,
+        ),
+        (
+            UnitOfArea.SQUARE_KILOMETERS,
+            "peer_distance",
+            UnitOfArea.SQUARE_KILOMETERS,
+            1000,
+            "1000",
+            "1000",
+            SensorDeviceClass.AREA,
+        ),
         # Distance
         (
             UnitOfLength.KILOMETERS,
@@ -1834,6 +1863,7 @@ async def test_non_numeric_device_class_with_unit_of_measurement(
     [
         SensorDeviceClass.APPARENT_POWER,
         SensorDeviceClass.AQI,
+        SensorDeviceClass.AREA,
         SensorDeviceClass.ATMOSPHERIC_PRESSURE,
         SensorDeviceClass.BATTERY,
         SensorDeviceClass.CO,

tests/components/sensor/test_recorder.py

@@ -227,6 +227,8 @@ async def assert_validation_result(
     ),
     [
         (None, "%", "%", "%", "unitless", 13.050847, -10, 30),
+        ("area", "m²", "m²", "m²", "area", 13.050847, -10, 30),
+        ("area", "mi²", "mi²", "mi²", "area", 13.050847, -10, 30),
         ("battery", "%", "%", "%", "unitless", 13.050847, -10, 30),
         ("battery", None, None, None, "unitless", 13.050847, -10, 30),
         ("distance", "m", "m", "m", "distance", 13.050847, -10, 30),
@@ -914,6 +916,8 @@ async def test_compile_hourly_statistics_wrong_unit(
         "factor",
     ),
     [
+        (US_CUSTOMARY_SYSTEM, "area", "m²", "m²", "m²", "area", 1),
+        (US_CUSTOMARY_SYSTEM, "area", "mi²", "mi²", "mi²", "area", 1),
         (US_CUSTOMARY_SYSTEM, "distance", "m", "m", "m", "distance", 1),
         (US_CUSTOMARY_SYSTEM, "distance", "mi", "mi", "mi", "distance", 1),
         (US_CUSTOMARY_SYSTEM, "energy", "kWh", "kWh", "kWh", "energy", 1),
@@ -926,6 +930,8 @@ async def test_compile_hourly_statistics_wrong_unit(
         (US_CUSTOMARY_SYSTEM, "volume", "ft³", "ft³", "ft³", "volume", 1),
         (US_CUSTOMARY_SYSTEM, "weight", "g", "g", "g", "mass", 1),
         (US_CUSTOMARY_SYSTEM, "weight", "oz", "oz", "oz", "mass", 1),
+        (METRIC_SYSTEM, "area", "m²", "m²", "m²", "area", 1),
+        (METRIC_SYSTEM, "area", "mi²", "mi²", "mi²", "area", 1),
         (METRIC_SYSTEM, "distance", "m", "m", "m", "distance", 1),
         (METRIC_SYSTEM, "distance", "mi", "mi", "mi", "distance", 1),
         (METRIC_SYSTEM, "energy", "kWh", "kWh", "kWh", "energy", 1),
@@ -2228,6 +2234,8 @@ async def test_compile_hourly_energy_statistics_multiple(
     [
         ("battery", "%", 30),
         ("battery", None, 30),
+        ("area", "m²", 30),
+        ("area", "mi²", 30),
         ("distance", "m", 30),
         ("distance", "mi", 30),
         ("humidity", "%", 30),
@@ -2336,6 +2344,8 @@ async def test_compile_hourly_statistics_partially_unavailable(
     [
         ("battery", "%", 30),
         ("battery", None, 30),
+        ("area", "m²", 30),
+        ("area", "mi²", 30),
         ("distance", "m", 30),
         ("distance", "mi", 30),
         ("humidity", "%", 30),
@@ -2438,6 +2448,10 @@ async def test_compile_hourly_statistics_fails(
         "statistic_type",
     ),
     [
+        ("measurement", "area", "m²", "m²", "m²", "area", "mean"),
+        ("measurement", "area", "mi²", "mi²", "mi²", "area", "mean"),
+        ("total", "area", "m²", "m²", "m²", "area", "sum"),
+        ("total", "area", "mi²", "mi²", "mi²", "area", "sum"),
         ("measurement", "battery", "%", "%", "%", "unitless", "mean"),
         ("measurement", "battery", None, None, None, "unitless", "mean"),
         ("measurement", "distance", "m", "m", "m", "distance", "mean"),

tests/helpers/test_template.py

@@ -24,6 +24,7 @@ from homeassistant.const import (
     ATTR_UNIT_OF_MEASUREMENT,
     STATE_ON,
     STATE_UNAVAILABLE,
+    UnitOfArea,
     UnitOfLength,
     UnitOfMass,
     UnitOfPrecipitationDepth,
@@ -61,6 +62,7 @@ def _set_up_units(hass: HomeAssistant) -> None:
     hass.config.units = UnitSystem(
         "custom",
         accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+        area=UnitOfArea.SQUARE_METERS,
         conversions={},
         length=UnitOfLength.METERS,
         mass=UnitOfMass.GRAMS,

tests/test_const.py

@@ -177,18 +177,24 @@ def test_deprecated_constants(
 
 
 @pytest.mark.parametrize(
-    ("replacement", "constant_name"),
+    ("replacement", "constant_name", "breaks_in_version"),
     [
-        (const.UnitOfLength.YARDS, "LENGTH_YARD"),
+        (const.UnitOfLength.YARDS, "LENGTH_YARD", "2025.1"),
-        (const.UnitOfSoundPressure.DECIBEL, "SOUND_PRESSURE_DB"),
+        (const.UnitOfSoundPressure.DECIBEL, "SOUND_PRESSURE_DB", "2025.1"),
-        (const.UnitOfSoundPressure.WEIGHTED_DECIBEL_A, "SOUND_PRESSURE_WEIGHTED_DBA"),
+        (
-        (const.UnitOfVolume.FLUID_OUNCES, "VOLUME_FLUID_OUNCE"),
+            const.UnitOfSoundPressure.WEIGHTED_DECIBEL_A,
+            "SOUND_PRESSURE_WEIGHTED_DBA",
+            "2025.1",
+        ),
+        (const.UnitOfVolume.FLUID_OUNCES, "VOLUME_FLUID_OUNCE", "2025.1"),
+        (const.UnitOfArea.SQUARE_METERS, "AREA_SQUARE_METERS", "2025.12"),
     ],
 )
 def test_deprecated_constant_name_changes(
     caplog: pytest.LogCaptureFixture,
     replacement: Enum,
     constant_name: str,
+    breaks_in_version: str,
 ) -> None:
     """Test deprecated constants, where the name is not the same as the enum value."""
     import_and_test_deprecated_constant(
@@ -197,7 +203,7 @@ def test_deprecated_constant_name_changes(
         constant_name,
         f"{replacement.__class__.__name__}.{replacement.name}",
         replacement,
-        "2025.1",
+        breaks_in_version,
     )
 
 

tests/util/test_unit_conversion.py

@@ -11,6 +11,7 @@ from homeassistant.const import (
     CONCENTRATION_PARTS_PER_BILLION,
     CONCENTRATION_PARTS_PER_MILLION,
     PERCENTAGE,
+    UnitOfArea,
     UnitOfBloodGlucoseConcentration,
     UnitOfConductivity,
     UnitOfDataRate,
@@ -32,6 +33,7 @@ from homeassistant.const import (
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.util import unit_conversion
 from homeassistant.util.unit_conversion import (
+    AreaConverter,
     BaseUnitConverter,
     BloodGlucoseConcentrationConverter,
     ConductivityConverter,
@@ -61,6 +63,7 @@ INVALID_SYMBOL = "bob"
 _ALL_CONVERTERS: dict[type[BaseUnitConverter], list[str | None]] = {
     converter: sorted(converter.VALID_UNITS, key=lambda x: (x is None, x))
     for converter in (
+        AreaConverter,
         BloodGlucoseConcentrationConverter,
         ConductivityConverter,
         DataRateConverter,
@@ -83,6 +86,7 @@ _ALL_CONVERTERS: dict[type[BaseUnitConverter], list[str | None]] = {
 
 # Dict containing all converters with a corresponding unit ratio.
 _GET_UNIT_RATIO: dict[type[BaseUnitConverter], tuple[str | None, str | None, float]] = {
+    AreaConverter: (UnitOfArea.SQUARE_KILOMETERS, UnitOfArea.SQUARE_METERS, 0.000001),
     BloodGlucoseConcentrationConverter: (
         UnitOfBloodGlucoseConcentration.MILLIGRAMS_PER_DECILITER,
         UnitOfBloodGlucoseConcentration.MILLIMOLE_PER_LITER,
@@ -138,6 +142,62 @@ _GET_UNIT_RATIO: dict[type[BaseUnitConverter], tuple[str | None, str | None, flo
 _CONVERTED_VALUE: dict[
     type[BaseUnitConverter], list[tuple[float, str | None, float, str | None]]
 ] = {
+    AreaConverter: [
+        # Square Meters to other units
+        (5, UnitOfArea.SQUARE_METERS, 50000, UnitOfArea.SQUARE_CENTIMETERS),
+        (5, UnitOfArea.SQUARE_METERS, 5000000, UnitOfArea.SQUARE_MILLIMETERS),
+        (5, UnitOfArea.SQUARE_METERS, 0.000005, UnitOfArea.SQUARE_KILOMETERS),
+        (5, UnitOfArea.SQUARE_METERS, 7750.015500031001, UnitOfArea.SQUARE_INCHES),
+        (5, UnitOfArea.SQUARE_METERS, 53.81955, UnitOfArea.SQUARE_FEET),
+        (5, UnitOfArea.SQUARE_METERS, 5.979950231505403, UnitOfArea.SQUARE_YARDS),
+        (5, UnitOfArea.SQUARE_METERS, 1.9305107927122295e-06, UnitOfArea.SQUARE_MILES),
+        (5, UnitOfArea.SQUARE_METERS, 0.0012355269073358272, UnitOfArea.ACRES),
+        (5, UnitOfArea.SQUARE_METERS, 0.0005, UnitOfArea.HECTARES),
+        # Square Kilometers to other units
+        (1, UnitOfArea.SQUARE_KILOMETERS, 1000000, UnitOfArea.SQUARE_METERS),
+        (1, UnitOfArea.SQUARE_KILOMETERS, 1e10, UnitOfArea.SQUARE_CENTIMETERS),
+        (1, UnitOfArea.SQUARE_KILOMETERS, 1e12, UnitOfArea.SQUARE_MILLIMETERS),
+        (5, UnitOfArea.SQUARE_KILOMETERS, 1.9305107927122296, UnitOfArea.SQUARE_MILES),
+        (5, UnitOfArea.SQUARE_KILOMETERS, 1235.5269073358272, UnitOfArea.ACRES),
+        (5, UnitOfArea.SQUARE_KILOMETERS, 500, UnitOfArea.HECTARES),
+        # Acres to other units
+        (5, UnitOfArea.ACRES, 20234.3, UnitOfArea.SQUARE_METERS),
+        (5, UnitOfArea.ACRES, 202342821.11999995, UnitOfArea.SQUARE_CENTIMETERS),
+        (5, UnitOfArea.ACRES, 20234282111.999992, UnitOfArea.SQUARE_MILLIMETERS),
+        (5, UnitOfArea.ACRES, 0.0202343, UnitOfArea.SQUARE_KILOMETERS),
+        (5, UnitOfArea.ACRES, 217800, UnitOfArea.SQUARE_FEET),
+        (5, UnitOfArea.ACRES, 24200.0, UnitOfArea.SQUARE_YARDS),
+        (5, UnitOfArea.ACRES, 0.0078125, UnitOfArea.SQUARE_MILES),
+        (5, UnitOfArea.ACRES, 2.02343, UnitOfArea.HECTARES),
+        # Hectares to other units
+        (5, UnitOfArea.HECTARES, 50000, UnitOfArea.SQUARE_METERS),
+        (5, UnitOfArea.HECTARES, 500000000, UnitOfArea.SQUARE_CENTIMETERS),
+        (5, UnitOfArea.HECTARES, 50000000000.0, UnitOfArea.SQUARE_MILLIMETERS),
+        (5, UnitOfArea.HECTARES, 0.019305107927122298, UnitOfArea.SQUARE_MILES),
+        (5, UnitOfArea.HECTARES, 538195.5, UnitOfArea.SQUARE_FEET),
+        (5, UnitOfArea.HECTARES, 59799.50231505403, UnitOfArea.SQUARE_YARDS),
+        (5, UnitOfArea.HECTARES, 12.355269073358272, UnitOfArea.ACRES),
+        # Square Miles to other units
+        (5, UnitOfArea.SQUARE_MILES, 12949940.551679997, UnitOfArea.SQUARE_METERS),
+        (5, UnitOfArea.SQUARE_MILES, 129499405516.79997, UnitOfArea.SQUARE_CENTIMETERS),
+        (5, UnitOfArea.SQUARE_MILES, 12949940551679.996, UnitOfArea.SQUARE_MILLIMETERS),
+        (5, UnitOfArea.SQUARE_MILES, 1294.9940551679997, UnitOfArea.HECTARES),
+        (5, UnitOfArea.SQUARE_MILES, 3200, UnitOfArea.ACRES),
+        # Square Yards to other units
+        (5, UnitOfArea.SQUARE_YARDS, 4.1806367999999985, UnitOfArea.SQUARE_METERS),
+        (5, UnitOfArea.SQUARE_YARDS, 41806.4, UnitOfArea.SQUARE_CENTIMETERS),
+        (5, UnitOfArea.SQUARE_YARDS, 4180636.7999999984, UnitOfArea.SQUARE_MILLIMETERS),
+        (
+            5,
+            UnitOfArea.SQUARE_YARDS,
+            4.180636799999998e-06,
+            UnitOfArea.SQUARE_KILOMETERS,
+        ),
+        (5, UnitOfArea.SQUARE_YARDS, 45.0, UnitOfArea.SQUARE_FEET),
+        (5, UnitOfArea.SQUARE_YARDS, 6479.999999999998, UnitOfArea.SQUARE_INCHES),
+        (5, UnitOfArea.SQUARE_YARDS, 1.6141528925619832e-06, UnitOfArea.SQUARE_MILES),
+        (5, UnitOfArea.SQUARE_YARDS, 0.0010330578512396695, UnitOfArea.ACRES),
+    ],
     BloodGlucoseConcentrationConverter: [
         (
             90,

tests/util/test_unit_system.py

@@ -7,12 +7,14 @@ import pytest
 from homeassistant.components.sensor import DEVICE_CLASS_UNITS, SensorDeviceClass
 from homeassistant.const import (
     ACCUMULATED_PRECIPITATION,
+    AREA,
     LENGTH,
     MASS,
     PRESSURE,
     TEMPERATURE,
     VOLUME,
     WIND_SPEED,
+    UnitOfArea,
     UnitOfLength,
     UnitOfMass,
     UnitOfPrecipitationDepth,
@@ -44,6 +46,7 @@ def test_invalid_units() -> None:
         UnitSystem(
             SYSTEM_NAME,
             accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+            area=UnitOfArea.SQUARE_METERS,
             conversions={},
             length=UnitOfLength.METERS,
             mass=UnitOfMass.GRAMS,
@@ -57,6 +60,7 @@ def test_invalid_units() -> None:
         UnitSystem(
             SYSTEM_NAME,
             accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+            area=UnitOfArea.SQUARE_METERS,
             conversions={},
             length=INVALID_UNIT,
             mass=UnitOfMass.GRAMS,
@@ -70,6 +74,7 @@ def test_invalid_units() -> None:
         UnitSystem(
             SYSTEM_NAME,
             accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+            area=UnitOfArea.SQUARE_METERS,
             conversions={},
             length=UnitOfLength.METERS,
             mass=UnitOfMass.GRAMS,
@@ -83,6 +88,7 @@ def test_invalid_units() -> None:
         UnitSystem(
             SYSTEM_NAME,
             accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+            area=UnitOfArea.SQUARE_METERS,
             conversions={},
             length=UnitOfLength.METERS,
             mass=UnitOfMass.GRAMS,
@@ -96,6 +102,7 @@ def test_invalid_units() -> None:
         UnitSystem(
             SYSTEM_NAME,
             accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+            area=UnitOfArea.SQUARE_METERS,
             conversions={},
             length=UnitOfLength.METERS,
             mass=INVALID_UNIT,
@@ -109,6 +116,7 @@ def test_invalid_units() -> None:
         UnitSystem(
             SYSTEM_NAME,
             accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+            area=UnitOfArea.SQUARE_METERS,
             conversions={},
             length=UnitOfLength.METERS,
             mass=UnitOfMass.GRAMS,
@@ -122,6 +130,21 @@ def test_invalid_units() -> None:
         UnitSystem(
             SYSTEM_NAME,
             accumulated_precipitation=INVALID_UNIT,
+            area=UnitOfArea.SQUARE_METERS,
+            conversions={},
+            length=UnitOfLength.METERS,
+            mass=UnitOfMass.GRAMS,
+            pressure=UnitOfPressure.PA,
+            temperature=UnitOfTemperature.CELSIUS,
+            volume=UnitOfVolume.LITERS,
+            wind_speed=UnitOfSpeed.METERS_PER_SECOND,
+        )
+
+    with pytest.raises(ValueError):
+        UnitSystem(
+            SYSTEM_NAME,
+            accumulated_precipitation=UnitOfPrecipitationDepth.MILLIMETERS,
+            area=INVALID_UNIT,
             conversions={},
             length=UnitOfLength.METERS,
             mass=UnitOfMass.GRAMS,
@@ -146,6 +169,8 @@ def test_invalid_value() -> None:
         METRIC_SYSTEM.pressure("50Pa", UnitOfPressure.PA)
     with pytest.raises(TypeError):
         METRIC_SYSTEM.accumulated_precipitation("50mm", UnitOfLength.MILLIMETERS)
+    with pytest.raises(TypeError):
+        METRIC_SYSTEM.area("2m²", UnitOfArea.SQUARE_METERS)
 
 
 def test_as_dict() -> None:
@@ -158,6 +183,7 @@ def test_as_dict() -> None:
         MASS: UnitOfMass.GRAMS,
         PRESSURE: UnitOfPressure.PA,
         ACCUMULATED_PRECIPITATION: UnitOfLength.MILLIMETERS,
+        AREA: UnitOfArea.SQUARE_METERS,
     }
 
     assert expected == METRIC_SYSTEM.as_dict()
@@ -303,6 +329,29 @@ def test_accumulated_precipitation_to_imperial() -> None:
     ) == pytest.approx(10, abs=1e-4)
 
 
+def test_area_same_unit() -> None:
+    """Test no conversion happens if to unit is same as from unit."""
+    assert METRIC_SYSTEM.area(5, METRIC_SYSTEM.area_unit) == 5
+
+
+def test_area_unknown_unit() -> None:
+    """Test no conversion happens if unknown unit."""
+    with pytest.raises(HomeAssistantError, match="is not a recognized .* unit"):
+        METRIC_SYSTEM.area(5, "abc")
+
+
+def test_area_to_metric() -> None:
+    """Test area conversion to metric system."""
+    assert METRIC_SYSTEM.area(25, METRIC_SYSTEM.area_unit) == 25
+    assert round(METRIC_SYSTEM.area(10, IMPERIAL_SYSTEM.area_unit), 1) == 0.9
+
+
+def test_area_to_imperial() -> None:
+    """Test area conversion to imperial system."""
+    assert IMPERIAL_SYSTEM.area(77, IMPERIAL_SYSTEM.area_unit) == 77
+    assert IMPERIAL_SYSTEM.area(25, METRIC_SYSTEM.area_unit) == 269.09776041774313
+
+
 def test_properties() -> None:
     """Test the unit properties are returned as expected."""
     assert METRIC_SYSTEM.length_unit == UnitOfLength.KILOMETERS
@@ -312,6 +361,7 @@ def test_properties() -> None:
     assert METRIC_SYSTEM.volume_unit == UnitOfVolume.LITERS
     assert METRIC_SYSTEM.pressure_unit == UnitOfPressure.PA
     assert METRIC_SYSTEM.accumulated_precipitation_unit == UnitOfLength.MILLIMETERS
+    assert METRIC_SYSTEM.area_unit == UnitOfArea.SQUARE_METERS
 
 
 @pytest.mark.parametrize(
@@ -338,6 +388,18 @@ def test_get_unit_system_invalid(key: str) -> None:
 @pytest.mark.parametrize(
     ("device_class", "original_unit", "state_unit"),
     [
+        # Test area conversion
+        (SensorDeviceClass.AREA, UnitOfArea.SQUARE_FEET, UnitOfArea.SQUARE_METERS),
+        (
+            SensorDeviceClass.AREA,
+            UnitOfArea.SQUARE_INCHES,
+            UnitOfArea.SQUARE_CENTIMETERS,
+        ),
+        (SensorDeviceClass.AREA, UnitOfArea.SQUARE_MILES, UnitOfArea.SQUARE_KILOMETERS),
+        (SensorDeviceClass.AREA, UnitOfArea.SQUARE_YARDS, UnitOfArea.SQUARE_METERS),
+        (SensorDeviceClass.AREA, UnitOfArea.ACRES, UnitOfArea.HECTARES),
+        (SensorDeviceClass.AREA, UnitOfArea.SQUARE_KILOMETERS, None),
+        (SensorDeviceClass.AREA, "very_long", None),
         # Test atmospheric pressure
         (
             SensorDeviceClass.ATMOSPHERIC_PRESSURE,
@@ -495,6 +557,13 @@ def test_get_metric_converted_unit_(
 
 
 UNCONVERTED_UNITS_METRIC_SYSTEM = {
+    SensorDeviceClass.AREA: (
+        UnitOfArea.SQUARE_MILLIMETERS,
+        UnitOfArea.SQUARE_CENTIMETERS,
+        UnitOfArea.SQUARE_METERS,
+        UnitOfArea.SQUARE_KILOMETERS,
+        UnitOfArea.HECTARES,
+    ),
     SensorDeviceClass.ATMOSPHERIC_PRESSURE: (UnitOfPressure.HPA,),
     SensorDeviceClass.DISTANCE: (
         UnitOfLength.CENTIMETERS,
@@ -544,6 +613,7 @@ UNCONVERTED_UNITS_METRIC_SYSTEM = {
 @pytest.mark.parametrize(
     "device_class",
     [
+        SensorDeviceClass.AREA,
         SensorDeviceClass.ATMOSPHERIC_PRESSURE,
         SensorDeviceClass.DISTANCE,
         SensorDeviceClass.GAS,
@@ -572,6 +642,21 @@ def test_metric_converted_units(device_class: SensorDeviceClass) -> None:
 @pytest.mark.parametrize(
     ("device_class", "original_unit", "state_unit"),
     [
+        # Test area conversion
+        (
+            SensorDeviceClass.AREA,
+            UnitOfArea.SQUARE_MILLIMETERS,
+            UnitOfArea.SQUARE_INCHES,
+        ),
+        (
+            SensorDeviceClass.AREA,
+            UnitOfArea.SQUARE_CENTIMETERS,
+            UnitOfArea.SQUARE_INCHES,
+        ),
+        (SensorDeviceClass.AREA, UnitOfArea.SQUARE_METERS, UnitOfArea.SQUARE_FEET),
+        (SensorDeviceClass.AREA, UnitOfArea.SQUARE_KILOMETERS, UnitOfArea.SQUARE_MILES),
+        (SensorDeviceClass.AREA, UnitOfArea.HECTARES, UnitOfArea.ACRES),
+        (SensorDeviceClass.AREA, "very_area", None),
         # Test atmospheric pressure
         (
             SensorDeviceClass.ATMOSPHERIC_PRESSURE,
@@ -721,6 +806,13 @@ def test_get_us_converted_unit(
 
 
 UNCONVERTED_UNITS_US_SYSTEM = {
+    SensorDeviceClass.AREA: (
+        UnitOfArea.SQUARE_FEET,
+        UnitOfArea.SQUARE_INCHES,
+        UnitOfArea.SQUARE_MILES,
+        UnitOfArea.SQUARE_YARDS,
+        UnitOfArea.ACRES,
+    ),
     SensorDeviceClass.ATMOSPHERIC_PRESSURE: (UnitOfPressure.INHG,),
     SensorDeviceClass.DISTANCE: (
         UnitOfLength.FEET,