Hi
If you are concerned that distance estimations are inaccurate, then the following steps may help:
Check your personal information:
- Actiivity-related estimations depend, in part, on your personal information.
- To check that this is accurate:
- On your iPhone, in the Watch app, go to: My Watch (tab) > Health > Edit - tap and adjust items, then tap on Done.
Check your Location Services settings:
- On your iPhone, go to: Settings > Privacy > Location Services:
- Check that Location Services (the main setting at the top) is turned on.
- In the list of apps beneath, check that Apple Watch Workout is set to While Using.
- Also enable options under System Services including Motion Calibration & Distance, Wi-Fi Networking and Mobile Network Search.
When recording specific fitness activities, be sure to use the Workout app and to choose the activity type that most closely matches your workout.
- This enables your watch to use the most appropriate sensors and data sources when tracking results.
- Work out with your Apple Watch - Apple Support
Allow the arm on which you are wearing your Apple Watch to swing naturally as you move around during daily wear and to move as expected during workouts:
- During general daily wear and when using the Workout app to record workouts when GPS data is either not relevant or not available, the Activity app and Workout app track your arm motion (measured by the accelerometer) when estimating results including steps.
Calibrate your Apple Watch, including resetting any existing calibration data:
- Calibration teaches your Apple Watch how your arm movements relate to your stride lengths at different speeds when you are walking and/or running. It does this, during outdoor walk and/or outdoor run workouts that are recorded via the Workout app, by comparing data from the accelerometer with GPS (Location Services) data.
- To calibrate your Apple Watch - and to reset existing calibration data - follow the instructions here:
- Resetting your calibration data and calibrating afresh can be equally as helpful for Series 3 models and will not erase your Activity history.
If the issue still persists, then I suggest that you contact Apple Support (remote diagnostics and/or mail-in service may be available, if required), make a Genius Bar reservation or visit an Apple Authorised Service Provider for assistance:
- US: Apple Watch Service Answer Center - Apple Support
- Elsewhere: Select your country for Apple Watch service and repair information
More information:
Get the most accurate measurements using your Apple Watch - Apple Support