diff --git a/homeassistant/components/bluesound/media_player.py b/homeassistant/components/bluesound/media_player.py
index 1d46af2cc4b..97985a74300 100644
--- a/homeassistant/components/bluesound/media_player.py
+++ b/homeassistant/components/bluesound/media_player.py
@@ -770,7 +770,7 @@ class BluesoundPlayer(MediaPlayerEntity):
 
     async def async_set_volume_level(self, volume: float) -> None:
         """Send volume_up command to media player."""
-        volume = int(volume * 100)
+        volume = int(round(volume * 100))
         volume = min(100, volume)
         volume = max(0, volume)
 
diff --git a/tests/components/bluesound/test_media_player.py b/tests/components/bluesound/test_media_player.py
index 894528265e1..0bf615de3da 100644
--- a/tests/components/bluesound/test_media_player.py
+++ b/tests/components/bluesound/test_media_player.py
@@ -345,3 +345,31 @@ async def test_attr_bluesound_group(
     ).attributes.get("bluesound_group")
 
     assert attr_bluesound_group == ["player-name1111", "player-name2222"]
+
+
+async def test_volume_up_from_6_to_7(
+    hass: HomeAssistant,
+    setup_config_entry: None,
+    player_mocks: PlayerMocks,
+) -> None:
+    """Test the media player volume up from 6 to 7.
+
+    This fails if if rounding is not done correctly. See https://github.com/home-assistant/core/issues/129956 for more details.
+    """
+    player_mocks.player_data.status_long_polling_mock.set(
+        dataclasses.replace(
+            player_mocks.player_data.status_long_polling_mock.get(), volume=6
+        )
+    )
+
+    # give the long polling loop a chance to update the state; this could be any async call
+    await hass.async_block_till_done()
+
+    await hass.services.async_call(
+        MEDIA_PLAYER_DOMAIN,
+        SERVICE_VOLUME_UP,
+        {ATTR_ENTITY_ID: "media_player.player_name1111"},
+        blocking=True,
+    )
+
+    player_mocks.player_data.player.volume.assert_called_once_with(level=7)