By initiating the calibration process, you can get more accurate readings for calorie, distance, Move, and Exercise estimations in the Watch’s Activity app, and also improved calculations in the Workout app.
By following the steps below, you’ll start calibrating the device’s accelerometer and improve Apple Watch’s accuracy by allowing it to learn your personal stride patterns at various speeds:
- Bring your iPhone and your Apple Watch.
- Find an open, flat area outside that offers good GPS reception and clear skies.
Make sure that Location Services is on. To check the setting on your iPhone, tap Settings > Privacy > Location Services.
Make sure that Motion Calibration & Distance is on. To check the setting on your iPhone, tap Settings > Privacy > Location Services > System Services.
Hold your iPhone in your hand, or attach it to your body with an armband (preferably) or waistband.
I’ve also heard that the first time you wanna go running or work out, take the iPhone with you for the first couple of times so it can calibrate and learn your step pattern. After the first couple of times of taking both devices with you whilst exercising you can then leave your iPhone at home, knowing that the Apple Watch will correctly record your workout data and sync the data back to the iPhone when you have finished.