Apple Watch and treadmill distance don't match?

Your watch and treadmill can report different distances for the same run. The watch estimates indoor distance from motion; the treadmill has its own measurement. Neither number is guaranteed to be exact, so compare a few runs before drawing a conclusion.

Correct a run in RunToMax

After a treadmill run recorded in RunToMax, you can enter the belt distance in the Watch summary. The calibration card is available for treadmill runs with recorded steps.

1. Finish your treadmill run and open its summary on the Watch.
2. Find Calibrate and enter the distance shown on the treadmill. Check the units first.
3. Tap Save calibration. Check the updated summary and look for any Apple Health sync or retry message.

RunToMax uses the entry for this run and as a baseline for future treadmill runs. It may take time to sync, and a correction cannot establish which device was closest to the true distance.

Check your Apple Watch calibration

For Apple’s Workout app, Apple recommends checking Location Services → System Services → Motion Calibration & Distance on your iPhone, then doing an Outdoor Walk or Outdoor Run in a flat, open area for about 20 minutes at your usual pace. See Apple’s calibration instructions for details and different speeds. This is Apple’s procedure; it is separate from entering a belt distance in RunToMax.

Still seeing a difference?

Check that the treadmill starts at zero and compare the same elapsed portion of the workout. Calibration may help but won’t eliminate every discrepancy. If a RunToMax correction fails, follow the retry message, check Health permissions, and contact support with your app and device versions.

Using another running app? Check whether it offers its own treadmill correction, or follow the watch maker’s calibration guidance.

Explore RunToMax on Apple Watch · Create intervals in RunToMax