diff --git a/homeassistant/components/number/__init__.py b/homeassistant/components/number/__init__.py
index e4ed8bb1d3e..0cdb9465360 100644
--- a/homeassistant/components/number/__init__.py
+++ b/homeassistant/components/number/__init__.py
@@ -24,7 +24,6 @@ from homeassistant.helpers.entity import Entity, EntityDescription
 from homeassistant.helpers.entity_component import EntityComponent
 from homeassistant.helpers.restore_state import ExtraStoredData, RestoreEntity
 from homeassistant.helpers.typing import ConfigType
-from homeassistant.util.unit_conversion import BaseUnitConverter, TemperatureConverter
 
 from .const import (
     ATTR_MAX,
@@ -36,7 +35,10 @@ from .const import (
     DEFAULT_STEP,
     DOMAIN,
     SERVICE_SET_VALUE,
+    UNIT_CONVERTERS,
+    NumberDeviceClass,
 )
+from .websocket_api import async_setup as async_setup_ws_api
 
 SCAN_INTERVAL = timedelta(seconds=30)
 
@@ -46,297 +48,6 @@ MIN_TIME_BETWEEN_SCANS = timedelta(seconds=10)
 
 _LOGGER = logging.getLogger(__name__)
 
-
-class NumberDeviceClass(StrEnum):
-    """Device class for numbers."""
-
-    # NumberDeviceClass should be aligned with SensorDeviceClass
-
-    APPARENT_POWER = "apparent_power"
-    """Apparent power.
-
-    Unit of measurement: `VA`
-    """
-
-    AQI = "aqi"
-    """Air Quality Index.
-
-    Unit of measurement: `None`
-    """
-
-    ATMOSPHERIC_PRESSURE = "atmospheric_pressure"
-    """Atmospheric pressure.
-
-    Unit of measurement: `UnitOfPressure` units
-    """
-
-    BATTERY = "battery"
-    """Percentage of battery that is left.
-
-    Unit of measurement: `%`
-    """
-
-    CO = "carbon_monoxide"
-    """Carbon Monoxide gas concentration.
-
-    Unit of measurement: `ppm` (parts per million)
-    """
-
-    CO2 = "carbon_dioxide"
-    """Carbon Dioxide gas concentration.
-
-    Unit of measurement: `ppm` (parts per million)
-    """
-
-    CURRENT = "current"
-    """Current.
-
-    Unit of measurement: `A`,  `mA`
-    """
-
-    DATA_RATE = "data_rate"
-    """Data rate.
-
-    Unit of measurement: UnitOfDataRate
-    """
-
-    DATA_SIZE = "data_size"
-    """Data size.
-
-    Unit of measurement: UnitOfInformation
-    """
-
-    DISTANCE = "distance"
-    """Generic distance.
-
-    Unit of measurement: `LENGTH_*` units
-    - SI /metric: `mm`, `cm`, `m`, `km`
-    - USCS / imperial: `in`, `ft`, `yd`, `mi`
-    """
-
-    ENERGY = "energy"
-    """Energy.
-
-    Unit of measurement: `Wh`, `kWh`, `MWh`, `GJ`
-    """
-
-    FREQUENCY = "frequency"
-    """Frequency.
-
-    Unit of measurement: `Hz`, `kHz`, `MHz`, `GHz`
-    """
-
-    GAS = "gas"
-    """Gas.
-
-    Unit of measurement:
-    - SI / metric: `m³`
-    - USCS / imperial: `ft³`, `CCF`
-    """
-
-    HUMIDITY = "humidity"
-    """Relative humidity.
-
-    Unit of measurement: `%`
-    """
-
-    ILLUMINANCE = "illuminance"
-    """Illuminance.
-
-    Unit of measurement: `lx`
-    """
-
-    IRRADIANCE = "irradiance"
-    """Irradiance.
-
-    Unit of measurement:
-    - SI / metric: `W/m²`
-    - USCS / imperial: `BTU/(h⋅ft²)`
-    """
-
-    MOISTURE = "moisture"
-    """Moisture.
-
-    Unit of measurement: `%`
-    """
-
-    MONETARY = "monetary"
-    """Amount of money.
-
-    Unit of measurement: ISO4217 currency code
-
-    See https://en.wikipedia.org/wiki/ISO_4217#Active_codes for active codes
-    """
-
-    NITROGEN_DIOXIDE = "nitrogen_dioxide"
-    """Amount of NO2.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    NITROGEN_MONOXIDE = "nitrogen_monoxide"
-    """Amount of NO.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    NITROUS_OXIDE = "nitrous_oxide"
-    """Amount of N2O.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    OZONE = "ozone"
-    """Amount of O3.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    PM1 = "pm1"
-    """Particulate matter <= 0.1 μm.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    PM10 = "pm10"
-    """Particulate matter <= 10 μm.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    PM25 = "pm25"
-    """Particulate matter <= 2.5 μm.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    POWER_FACTOR = "power_factor"
-    """Power factor.
-
-    Unit of measurement: `%`, `None`
-    """
-
-    POWER = "power"
-    """Power.
-
-    Unit of measurement: `W`, `kW`
-    """
-
-    PRECIPITATION = "precipitation"
-    """Accumulated precipitation.
-
-    Unit of measurement: UnitOfPrecipitationDepth
-    - SI / metric: `cm`, `mm`
-    - USCS / imperial: `in`
-    """
-
-    PRECIPITATION_INTENSITY = "precipitation_intensity"
-    """Precipitation intensity.
-
-    Unit of measurement: UnitOfVolumetricFlux
-    - SI /metric: `mm/d`, `mm/h`
-    - USCS / imperial: `in/d`, `in/h`
-    """
-
-    PRESSURE = "pressure"
-    """Pressure.
-
-    Unit of measurement:
-    - `mbar`, `cbar`, `bar`
-    - `Pa`, `hPa`, `kPa`
-    - `inHg`
-    - `psi`
-    """
-
-    REACTIVE_POWER = "reactive_power"
-    """Reactive power.
-
-    Unit of measurement: `var`
-    """
-
-    SIGNAL_STRENGTH = "signal_strength"
-    """Signal strength.
-
-    Unit of measurement: `dB`, `dBm`
-    """
-
-    SOUND_PRESSURE = "sound_pressure"
-    """Sound pressure.
-
-    Unit of measurement: `dB`, `dBA`
-    """
-
-    SPEED = "speed"
-    """Generic speed.
-
-    Unit of measurement: `SPEED_*` units or `UnitOfVolumetricFlux`
-    - SI /metric: `mm/d`, `mm/h`, `m/s`, `km/h`
-    - USCS / imperial: `in/d`, `in/h`, `ft/s`, `mph`
-    - Nautical: `kn`
-    """
-
-    SULPHUR_DIOXIDE = "sulphur_dioxide"
-    """Amount of SO2.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    TEMPERATURE = "temperature"
-    """Temperature.
-
-    Unit of measurement: `°C`, `°F`
-    """
-
-    VOLATILE_ORGANIC_COMPOUNDS = "volatile_organic_compounds"
-    """Amount of VOC.
-
-    Unit of measurement: `µg/m³`
-    """
-
-    VOLTAGE = "voltage"
-    """Voltage.
-
-    Unit of measurement: `V`, `mV`
-    """
-
-    VOLUME = "volume"
-    """Generic volume.
-
-    Unit of measurement: `VOLUME_*` units
-    - SI / metric: `mL`, `L`, `m³`
-    - USCS / imperial: `ft³`, `CCF`, `fl. oz.`, `gal` (warning: volumes expressed in
-    USCS/imperial units are currently assumed to be US volumes)
-    """
-
-    WATER = "water"
-    """Water.
-
-    Unit of measurement:
-    - SI / metric: `m³`, `L`
-    - USCS / imperial: `ft³`, `CCF`, `gal` (warning: volumes expressed in
-    USCS/imperial units are currently assumed to be US volumes)
-    """
-
-    WEIGHT = "weight"
-    """Generic weight, represents a measurement of an object's mass.
-
-    Weight is used instead of mass to fit with every day language.
-
-    Unit of measurement: `MASS_*` units
-    - SI / metric: `µg`, `mg`, `g`, `kg`
-    - USCS / imperial: `oz`, `lb`
-    """
-
-    WIND_SPEED = "wind_speed"
-    """Wind speed.
-
-    Unit of measurement: `SPEED_*` units
-    - SI /metric: `m/s`, `km/h`
-    - USCS / imperial: `ft/s`, `mph`
-    - Nautical: `kn`
-    """
-
-
 DEVICE_CLASSES_SCHEMA: Final = vol.All(vol.Lower, vol.Coerce(NumberDeviceClass))
 
 
@@ -348,10 +59,6 @@ class NumberMode(StrEnum):
     SLIDER = "slider"
 
 
-UNIT_CONVERTERS: dict[str, type[BaseUnitConverter]] = {
-    NumberDeviceClass.TEMPERATURE: TemperatureConverter,
-}
-
 # mypy: disallow-any-generics
 
 
@@ -360,6 +67,7 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     component = hass.data[DOMAIN] = EntityComponent[NumberEntity](
         _LOGGER, DOMAIN, hass, SCAN_INTERVAL
     )
+    async_setup_ws_api(hass)
     await component.async_setup(config)
 
     component.async_register_entity_service(
diff --git a/homeassistant/components/number/const.py b/homeassistant/components/number/const.py
index 50390e7ab81..e9c4c741e54 100644
--- a/homeassistant/components/number/const.py
+++ b/homeassistant/components/number/const.py
@@ -1,7 +1,38 @@
 """Provides the constants needed for the component."""
+from __future__ import annotations
 
 from typing import Final
 
+from homeassistant.backports.enum import StrEnum
+from homeassistant.const import (
+    CONCENTRATION_MICROGRAMS_PER_CUBIC_METER,
+    CONCENTRATION_PARTS_PER_MILLION,
+    LIGHT_LUX,
+    PERCENTAGE,
+    POWER_VOLT_AMPERE_REACTIVE,
+    SIGNAL_STRENGTH_DECIBELS,
+    SIGNAL_STRENGTH_DECIBELS_MILLIWATT,
+    UnitOfApparentPower,
+    UnitOfDataRate,
+    UnitOfElectricCurrent,
+    UnitOfElectricPotential,
+    UnitOfEnergy,
+    UnitOfFrequency,
+    UnitOfInformation,
+    UnitOfIrradiance,
+    UnitOfLength,
+    UnitOfMass,
+    UnitOfPower,
+    UnitOfPrecipitationDepth,
+    UnitOfPressure,
+    UnitOfSoundPressure,
+    UnitOfSpeed,
+    UnitOfTemperature,
+    UnitOfVolume,
+    UnitOfVolumetricFlux,
+)
+from homeassistant.util.unit_conversion import BaseUnitConverter, TemperatureConverter
+
 ATTR_VALUE = "value"
 ATTR_MIN = "min"
 ATTR_MAX = "max"
@@ -19,3 +50,360 @@ SERVICE_SET_VALUE = "set_value"
 MODE_AUTO: Final = "auto"
 MODE_BOX: Final = "box"
 MODE_SLIDER: Final = "slider"
+
+
+class NumberDeviceClass(StrEnum):
+    """Device class for numbers."""
+
+    # NumberDeviceClass should be aligned with NumberDeviceClass
+
+    APPARENT_POWER = "apparent_power"
+    """Apparent power.
+
+    Unit of measurement: `VA`
+    """
+
+    AQI = "aqi"
+    """Air Quality Index.
+
+    Unit of measurement: `None`
+    """
+
+    ATMOSPHERIC_PRESSURE = "atmospheric_pressure"
+    """Atmospheric pressure.
+
+    Unit of measurement: `UnitOfPressure` units
+    """
+
+    BATTERY = "battery"
+    """Percentage of battery that is left.
+
+    Unit of measurement: `%`
+    """
+
+    CO = "carbon_monoxide"
+    """Carbon Monoxide gas concentration.
+
+    Unit of measurement: `ppm` (parts per million)
+    """
+
+    CO2 = "carbon_dioxide"
+    """Carbon Dioxide gas concentration.
+
+    Unit of measurement: `ppm` (parts per million)
+    """
+
+    CURRENT = "current"
+    """Current.
+
+    Unit of measurement: `A`,  `mA`
+    """
+
+    DATA_RATE = "data_rate"
+    """Data rate.
+
+    Unit of measurement: UnitOfDataRate
+    """
+
+    DATA_SIZE = "data_size"
+    """Data size.
+
+    Unit of measurement: UnitOfInformation
+    """
+
+    DISTANCE = "distance"
+    """Generic distance.
+
+    Unit of measurement: `LENGTH_*` units
+    - SI /metric: `mm`, `cm`, `m`, `km`
+    - USCS / imperial: `in`, `ft`, `yd`, `mi`
+    """
+
+    ENERGY = "energy"
+    """Energy.
+
+    Unit of measurement: `Wh`, `kWh`, `MWh`, `GJ`
+    """
+
+    FREQUENCY = "frequency"
+    """Frequency.
+
+    Unit of measurement: `Hz`, `kHz`, `MHz`, `GHz`
+    """
+
+    GAS = "gas"
+    """Gas.
+
+    Unit of measurement:
+    - SI / metric: `m³`
+    - USCS / imperial: `ft³`, `CCF`
+    """
+
+    HUMIDITY = "humidity"
+    """Relative humidity.
+
+    Unit of measurement: `%`
+    """
+
+    ILLUMINANCE = "illuminance"
+    """Illuminance.
+
+    Unit of measurement: `lx`
+    """
+
+    IRRADIANCE = "irradiance"
+    """Irradiance.
+
+    Unit of measurement:
+    - SI / metric: `W/m²`
+    - USCS / imperial: `BTU/(h⋅ft²)`
+    """
+
+    MOISTURE = "moisture"
+    """Moisture.
+
+    Unit of measurement: `%`
+    """
+
+    MONETARY = "monetary"
+    """Amount of money.
+
+    Unit of measurement: ISO4217 currency code
+
+    See https://en.wikipedia.org/wiki/ISO_4217#Active_codes for active codes
+    """
+
+    NITROGEN_DIOXIDE = "nitrogen_dioxide"
+    """Amount of NO2.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    NITROGEN_MONOXIDE = "nitrogen_monoxide"
+    """Amount of NO.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    NITROUS_OXIDE = "nitrous_oxide"
+    """Amount of N2O.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    OZONE = "ozone"
+    """Amount of O3.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    PM1 = "pm1"
+    """Particulate matter <= 0.1 μm.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    PM10 = "pm10"
+    """Particulate matter <= 10 μm.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    PM25 = "pm25"
+    """Particulate matter <= 2.5 μm.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    POWER_FACTOR = "power_factor"
+    """Power factor.
+
+    Unit of measurement: `%`, `None`
+    """
+
+    POWER = "power"
+    """Power.
+
+    Unit of measurement: `W`, `kW`
+    """
+
+    PRECIPITATION = "precipitation"
+    """Accumulated precipitation.
+
+    Unit of measurement: UnitOfPrecipitationDepth
+    - SI / metric: `cm`, `mm`
+    - USCS / imperial: `in`
+    """
+
+    PRECIPITATION_INTENSITY = "precipitation_intensity"
+    """Precipitation intensity.
+
+    Unit of measurement: UnitOfVolumetricFlux
+    - SI /metric: `mm/d`, `mm/h`
+    - USCS / imperial: `in/d`, `in/h`
+    """
+
+    PRESSURE = "pressure"
+    """Pressure.
+
+    Unit of measurement:
+    - `mbar`, `cbar`, `bar`
+    - `Pa`, `hPa`, `kPa`
+    - `inHg`
+    - `psi`
+    """
+
+    REACTIVE_POWER = "reactive_power"
+    """Reactive power.
+
+    Unit of measurement: `var`
+    """
+
+    SIGNAL_STRENGTH = "signal_strength"
+    """Signal strength.
+
+    Unit of measurement: `dB`, `dBm`
+    """
+
+    SOUND_PRESSURE = "sound_pressure"
+    """Sound pressure.
+
+    Unit of measurement: `dB`, `dBA`
+    """
+
+    SPEED = "speed"
+    """Generic speed.
+
+    Unit of measurement: `SPEED_*` units or `UnitOfVolumetricFlux`
+    - SI /metric: `mm/d`, `mm/h`, `m/s`, `km/h`
+    - USCS / imperial: `in/d`, `in/h`, `ft/s`, `mph`
+    - Nautical: `kn`
+    """
+
+    SULPHUR_DIOXIDE = "sulphur_dioxide"
+    """Amount of SO2.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    TEMPERATURE = "temperature"
+    """Temperature.
+
+    Unit of measurement: `°C`, `°F`
+    """
+
+    VOLATILE_ORGANIC_COMPOUNDS = "volatile_organic_compounds"
+    """Amount of VOC.
+
+    Unit of measurement: `µg/m³`
+    """
+
+    VOLTAGE = "voltage"
+    """Voltage.
+
+    Unit of measurement: `V`, `mV`
+    """
+
+    VOLUME = "volume"
+    """Generic volume.
+
+    Unit of measurement: `VOLUME_*` units
+    - SI / metric: `mL`, `L`, `m³`
+    - USCS / imperial: `ft³`, `CCF`, `fl. oz.`, `gal` (warning: volumes expressed in
+    USCS/imperial units are currently assumed to be US volumes)
+    """
+
+    WATER = "water"
+    """Water.
+
+    Unit of measurement:
+    - SI / metric: `m³`, `L`
+    - USCS / imperial: `ft³`, `CCF`, `gal` (warning: volumes expressed in
+    USCS/imperial units are currently assumed to be US volumes)
+    """
+
+    WEIGHT = "weight"
+    """Generic weight, represents a measurement of an object's mass.
+
+    Weight is used instead of mass to fit with every day language.
+
+    Unit of measurement: `MASS_*` units
+    - SI / metric: `µg`, `mg`, `g`, `kg`
+    - USCS / imperial: `oz`, `lb`
+    """
+
+    WIND_SPEED = "wind_speed"
+    """Wind speed.
+
+    Unit of measurement: `SPEED_*` units
+    - SI /metric: `m/s`, `km/h`
+    - USCS / imperial: `ft/s`, `mph`
+    - Nautical: `kn`
+    """
+
+
+DEVICE_CLASS_UNITS: dict[NumberDeviceClass, set[type[StrEnum] | str | None]] = {
+    NumberDeviceClass.APPARENT_POWER: set(UnitOfApparentPower),
+    NumberDeviceClass.AQI: {None},
+    NumberDeviceClass.ATMOSPHERIC_PRESSURE: set(UnitOfPressure),
+    NumberDeviceClass.BATTERY: {PERCENTAGE},
+    NumberDeviceClass.CO: {CONCENTRATION_PARTS_PER_MILLION},
+    NumberDeviceClass.CO2: {CONCENTRATION_PARTS_PER_MILLION},
+    NumberDeviceClass.CURRENT: set(UnitOfElectricCurrent),
+    NumberDeviceClass.DATA_RATE: set(UnitOfDataRate),
+    NumberDeviceClass.DATA_SIZE: set(UnitOfInformation),
+    NumberDeviceClass.DISTANCE: set(UnitOfLength),
+    NumberDeviceClass.ENERGY: set(UnitOfEnergy),
+    NumberDeviceClass.FREQUENCY: set(UnitOfFrequency),
+    NumberDeviceClass.GAS: {
+        UnitOfVolume.CENTUM_CUBIC_FEET,
+        UnitOfVolume.CUBIC_FEET,
+        UnitOfVolume.CUBIC_METERS,
+    },
+    NumberDeviceClass.HUMIDITY: {PERCENTAGE},
+    NumberDeviceClass.ILLUMINANCE: {LIGHT_LUX},
+    NumberDeviceClass.IRRADIANCE: set(UnitOfIrradiance),
+    NumberDeviceClass.MOISTURE: {PERCENTAGE},
+    NumberDeviceClass.NITROGEN_DIOXIDE: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.NITROGEN_MONOXIDE: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.NITROUS_OXIDE: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.OZONE: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.PM1: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.PM10: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.PM25: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.POWER_FACTOR: {PERCENTAGE, None},
+    NumberDeviceClass.POWER: {UnitOfPower.WATT, UnitOfPower.KILO_WATT},
+    NumberDeviceClass.PRECIPITATION: set(UnitOfPrecipitationDepth),
+    NumberDeviceClass.PRECIPITATION_INTENSITY: set(UnitOfVolumetricFlux),
+    NumberDeviceClass.PRESSURE: set(UnitOfPressure),
+    NumberDeviceClass.REACTIVE_POWER: {POWER_VOLT_AMPERE_REACTIVE},
+    NumberDeviceClass.SIGNAL_STRENGTH: {
+        SIGNAL_STRENGTH_DECIBELS,
+        SIGNAL_STRENGTH_DECIBELS_MILLIWATT,
+    },
+    NumberDeviceClass.SOUND_PRESSURE: set(UnitOfSoundPressure),
+    NumberDeviceClass.SPEED: set(UnitOfSpeed).union(set(UnitOfVolumetricFlux)),
+    NumberDeviceClass.SULPHUR_DIOXIDE: {CONCENTRATION_MICROGRAMS_PER_CUBIC_METER},
+    NumberDeviceClass.TEMPERATURE: {
+        UnitOfTemperature.CELSIUS,
+        UnitOfTemperature.FAHRENHEIT,
+    },
+    NumberDeviceClass.VOLATILE_ORGANIC_COMPOUNDS: {
+        CONCENTRATION_MICROGRAMS_PER_CUBIC_METER
+    },
+    NumberDeviceClass.VOLTAGE: set(UnitOfElectricPotential),
+    NumberDeviceClass.VOLUME: set(UnitOfVolume),
+    NumberDeviceClass.WATER: {
+        UnitOfVolume.CENTUM_CUBIC_FEET,
+        UnitOfVolume.CUBIC_FEET,
+        UnitOfVolume.CUBIC_METERS,
+        UnitOfVolume.GALLONS,
+        UnitOfVolume.LITERS,
+    },
+    NumberDeviceClass.WEIGHT: set(UnitOfMass),
+    NumberDeviceClass.WIND_SPEED: set(UnitOfSpeed),
+}
+
+UNIT_CONVERTERS: dict[str, type[BaseUnitConverter]] = {
+    NumberDeviceClass.TEMPERATURE: TemperatureConverter,
+}
diff --git a/homeassistant/components/number/websocket_api.py b/homeassistant/components/number/websocket_api.py
new file mode 100644
index 00000000000..eca280d7d43
--- /dev/null
+++ b/homeassistant/components/number/websocket_api.py
@@ -0,0 +1,35 @@
+"""The sensor websocket API."""
+from __future__ import annotations
+
+from typing import Any
+
+import voluptuous as vol
+
+from homeassistant.components import websocket_api
+from homeassistant.core import HomeAssistant, callback
+
+from .const import DEVICE_CLASS_UNITS, UNIT_CONVERTERS
+
+
+@callback
+def async_setup(hass: HomeAssistant) -> None:
+    """Set up the number websocket API."""
+    websocket_api.async_register_command(hass, ws_device_class_units)
+
+
+@callback
+@websocket_api.websocket_command(
+    {
+        vol.Required("type"): "number/device_class_convertible_units",
+        vol.Required("device_class"): str,
+    }
+)
+def ws_device_class_units(
+    hass: HomeAssistant, connection: websocket_api.ActiveConnection, msg: dict[str, Any]
+) -> None:
+    """Return supported units for a device class."""
+    device_class = msg["device_class"]
+    convertible_units = set()
+    if device_class in UNIT_CONVERTERS and device_class in DEVICE_CLASS_UNITS:
+        convertible_units = DEVICE_CLASS_UNITS[device_class]
+    connection.send_result(msg["id"], {"units": convertible_units})
diff --git a/tests/components/number/test_init.py b/tests/components/number/test_init.py
index f6b2c615123..e65913f1461 100644
--- a/tests/components/number/test_init.py
+++ b/tests/components/number/test_init.py
@@ -14,7 +14,13 @@ from homeassistant.components.number import (
     NumberEntity,
     NumberEntityDescription,
 )
-from homeassistant.components.sensor import SensorDeviceClass
+from homeassistant.components.number.const import (
+    DEVICE_CLASS_UNITS as NUMBER_DEVICE_CLASS_UNITS,
+)
+from homeassistant.components.sensor import (
+    DEVICE_CLASS_UNITS as SENSOR_DEVICE_CLASS_UNITS,
+    SensorDeviceClass,
+)
 from homeassistant.const import (
     ATTR_ENTITY_ID,
     ATTR_UNIT_OF_MEASUREMENT,
@@ -867,3 +873,11 @@ def test_device_classes_aligned():
 
         assert hasattr(NumberDeviceClass, device_class.name)
         assert getattr(NumberDeviceClass, device_class.name).value == device_class.value
+
+    for device_class in SENSOR_DEVICE_CLASS_UNITS:
+        if device_class in non_numeric_device_classes:
+            continue
+        assert (
+            SENSOR_DEVICE_CLASS_UNITS[device_class]
+            == NUMBER_DEVICE_CLASS_UNITS[device_class]
+        )
diff --git a/tests/components/number/test_websocket_api.py b/tests/components/number/test_websocket_api.py
new file mode 100644
index 00000000000..f920fddd420
--- /dev/null
+++ b/tests/components/number/test_websocket_api.py
@@ -0,0 +1,49 @@
+"""Test the number websocket API."""
+from pytest_unordered import unordered
+
+from homeassistant.components.number.const import DOMAIN
+from homeassistant.core import HomeAssistant
+from homeassistant.setup import async_setup_component
+
+
+async def test_device_class_units(hass: HomeAssistant, hass_ws_client) -> None:
+    """Test we can get supported units."""
+    assert await async_setup_component(hass, DOMAIN, {})
+
+    client = await hass_ws_client(hass)
+
+    # Device class with units which number allows customizing & converting
+    await client.send_json(
+        {
+            "id": 1,
+            "type": "number/device_class_convertible_units",
+            "device_class": "temperature",
+        }
+    )
+    msg = await client.receive_json()
+    assert msg["success"]
+    assert msg["result"] == {"units": unordered(["°F", "°C"])}
+
+    # Device class with units which number doesn't allow customizing & converting
+    await client.send_json(
+        {
+            "id": 2,
+            "type": "number/device_class_convertible_units",
+            "device_class": "energy",
+        }
+    )
+    msg = await client.receive_json()
+    assert msg["success"]
+    assert msg["result"] == {"units": []}
+
+    # Unknown device class
+    await client.send_json(
+        {
+            "id": 3,
+            "type": "number/device_class_convertible_units",
+            "device_class": "kebabsås",
+        }
+    )
+    msg = await client.receive_json()
+    assert msg["success"]
+    assert msg["result"] == {"units": unordered([])}