Change Weight Units on Apple Watch, Garmin & MyFitnessPal

To change weight units, use iPhone Health for Apple Watch, Units of Measure in Garmin Connect, or the Units setting in MyFitnessPal. The steps below cover kg, pounds and stone display options.

Where to change weight units

Apple Watch takes its weight display from the iPhone Health app. Garmin has separate settings for the watch and Garmin Connect, while MyFitnessPal stores the preference in your account. Changing a display unit should convert the value rather than change the underlying weight, but the menu names can vary by device model or app version.

UK users often think in stone for personal weight, kilograms at the gym, and pounds when reading American content. These settings remove that mental juggle when you know where to find them. You can convert your weight between kg and stone to check your figures as you go.

⌚ Apple Watch & Apple Health

Apple Watch does not have its own weight unit setting. All unit changes are made through the iPhone Health app and then sync automatically to the watch. Attempting to change units on the watch itself has no effect.

Step	Action	Detail
1	Open Health app on iPhone	Tap the Health app, not the Fitness app. They are separate.
2	Tap Browse (bottom right)	This opens the full list of health categories.
3	Select Body Measurements	Scroll down to find it, or use the search bar at the top.
4	Tap Weight	Your current weight entry will appear.
5	Scroll to Unit	At the bottom of the Weight screen, tap Unit.
6	Select your unit	Choose from kg, lbs, or stone. Changes apply immediately.
7	Sync to Apple Watch	Open Watch app → My Watch → Health → Health Details and confirm the unit.

Important: If your Apple Watch still shows the old unit after following these steps, unpairing and re-pairing the watch with your iPhone will force a full settings sync. This is particularly common after moving between countries with different regional defaults.

★ Common Apple Watch issue

You cannot change weight units directly on the Apple Watch itself. Every forum thread that suggests otherwise is referring to an older watchOS version. As of watchOS 10 and later, all body measurement unit changes must be made in the iPhone's Health app. The watch will update on next sync.

🛰️ Garmin Connect

Garmin separates watch settings from app settings. Changes made in the Garmin Connect app do not automatically update what your Garmin watch displays, and vice versa. You need to configure both independently if you want everything to match.

Steps: Garmin Watch (On-Device)

Step	Action	Detail
1	Hold the Up/Menu button	Hold until the settings menu appears on screen.
2	Scroll to System	Use the Down button to navigate.
3	Select Format	On some models this is labelled System > Units directly.
4	Select Units	Opens the full units sub-menu.
5	Select Weight	From here, choose kg, lbs, or stone. Changes save automatically.

Steps: Garmin Connect App (iOS & Android)

Step	Action	Detail
1	Open Garmin Connect	Tap the app and sign in.
2	Tap the profile icon (top left)	This opens your user profile.
3	Tap Settings	Then tap User Settings.
4	Select Units of Measure	Three options: Metric, Statute, or Statute UK.
5	Choose Statute UK	Enables stone and pounds as weight options.
6	Open weight data	Navigate to Health Stats > Weight in the app.
7	Tap the three dots (top right)	Select preferred display. This final step activates stone display and is easy to miss.

★ Garmin's Hidden Step

Setting Garmin Connect to 'Statute UK' is not enough on its own. Open your weight data and tap the three dots in the top-right corner to switch the display to stone and pounds. If you miss this second step, the app continues to show pounds.

🍽️ MyFitnessPal

MyFitnessPal offers stones and pounds as a full unit option alongside kilograms and pounds. The setting lives in your profile, and any change made in the app automatically updates the web version and vice versa. Past weight entries are retroactively converted when you switch units.

Steps: MyFitnessPal App (iOS & Android)

Step	Action	Detail
1	Open MyFitnessPal	Tap the app and log in.
2	Tap More (bottom right)	Icon shows three dots or lines depending on OS.
3	Tap Settings	Then navigate to My Account.
4	Tap Edit Profile	On some versions, tap your profile photo first.
5	Tap Units	Opens the full unit selection screen.
6	Tap Weight	Select from kg, lbs, or stones/lbs.
7	Save / Confirm	Tap OK or the checkmark. Data converts automatically.

Steps: MyFitnessPal Web

Step	Action	Detail
1	Go to myfitnesspal.com	Log in to your account.
2	Click My Home	In the top navigation bar.
3	Click Settings	From the dropdown menu.
4	Click Change Units	In the left-hand sidebar.
5	Change Weight unit	Select preferred unit from the dropdown.
6	Click Save Changes	Changes sync to the mobile app automatically.

Platform Comparison at a Glance

Platform	Where to Change	Units Available	Notes
Apple Health	Health app → Browse → Body Measurements → Weight → Unit	kg, lbs, stone	Watch syncs from iPhone only
Garmin Connect	Profile → Settings → Units of Measure → Statute UK	Metric / Statute / UK	Must also tap 3 dots in weight view
Garmin Watch	Menu → System → Format → Units → Weight	kg, lbs, stone	Independent of app. Set separately.
MyFitnessPal	More → Settings → My Account → Units → Weight	kg, lbs, stone/lbs	Historical entries auto-convert

Once your units are aligned, you can check your BMI accurately across all platforms.

Why These Settings Exist Separately

Each platform stores weight data in a single master unit internally, usually kilograms, the SI standard used in science and medicine. The unit you choose is a display preference, not a change to the stored data. Switching units therefore does not corrupt your historical records.

The disconnect between watch and app settings in Garmin's ecosystem exists because the watch operates as a standalone device that only syncs selected data rather than mirroring all account preferences. Apple took a different approach by tying the watch display entirely to the iPhone's Health app, which is why you cannot make the change on the watch itself.

Keep units consistent when tracking weight

Choose one display unit for everyday tracking, then check the unit before comparing readings between apps. If a value looks wrong after switching, compare the same entry in kilograms and use the kg-to-stone converter rather than entering a new measurement.

Frequently Asked Questions

How do I change weight to kg on Apple Watch?

You cannot change the unit directly on the Apple Watch. Open the Health app on your paired iPhone, tap Browse, then Body Measurements, then Weight, then Unit and select kg. The watch reflects the change on next sync.

How do I change Garmin weight units to stone?

In Garmin Connect, go to Profile > Settings > User Settings > Units of Measure and choose Statute UK. Then open your weight data and tap the three dots (top right) to switch to stone display.

How do I change MyFitnessPal from stone to kg?

In the app: More > Settings > My Account > Edit Profile > Units > Weight > select kg. On the website: My Home > Settings > Change Units.

Will changing units in MyFitnessPal affect old entries?

Yes. MyFitnessPal automatically converts all historical weight entries to the new unit. No data is lost.

Why does my Apple Watch show a different unit to my iPhone?

Update the unit in iPhone Health app and unpair/re-pair the watch to force a full settings sync.

Changing Units on Your Wearables: A Step-by-Step Guide