You can calibrate your Apple Watch to improve the accuracy of your distance, pace, and calorie measurements. Calibrating your watch can also help it learn your fitness level and stride, which improves accuracy when GPS is limited or unavailable.
Calibrate your Apple Watch
Before you try to calibrate your Apple Watch, check these settings on your iPhone:
- Tap Settings > Privacy > Location Services and make sure that Location Services is turned on.
- Tap Settings > Privacy > Location Services > System Services and make sure that Motion Calibration & Distance is turned on.
After you check the settings, you can calibrate your Apple Watch:
- While wearing your Apple Watch, go to a flat, open outdoor area that offers good GPS reception and clear skies.
- If you don’t have an Apple Watch Series 2, bring your iPhone for GPS. Hold your iPhone in your hand, or wear it on an armband or waistband.
- Open the Workout app and choose an Outdoor Walk or Outdoor Run.
- Choose your goal or select Open. Tap Start.
- Walk or run at your normal pace for about 20 minutes.
If you don't have time to finish the workout, you can complete 20 minutes over multiple outdoor Workout sessions. If you work out at different speeds, you should also calibrate for 20 minutes at each of the speeds that you walk or run.
Whenever you walk or run outside using the above steps, your Apple Watch continues to calibrate the accelerometer by learning your stride length at different speeds. Calibration can also improve the accuracy of your calorie calculations in the Workout app, and the calorie, distance, Move, and Exercise calculations in the Activity app.
Reset your calibration data
If you want to reset your calibration data, open the Apple Watch app on your iPhone. Tap the My Watch tab, then tap Privacy > Motion & Fitness > Reset Calibration Data.
Update your personal information
Your personal information, such as your height, weight, gender, and age, is one of the things your Apple Watch uses to calculate how many calories you burn and more. To update your personal information:
- Open the Apple Watch app on your iPhone.
- Tap the My Watch tab.
- Tap Health > Edit.
- Tap the item that you want to change and adjust it.
- Tap Done.