Apple Watch Indoor Walk / treadmill distance ~30–50% low after watchOS 27 — calibration failed

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Level 1

5 points

Apple Watch Indoor Walk / treadmill distance ~30–50% low after watchOS 27 — calibration failed

After updating to watchOS 27, my Apple Watch Indoor Walk / treadmill distance is suddenly undercounting by about 30–50% (previously on older watchOS it was sometimes ~10–20% high). Resetting Fitness Calibration Data and doing Outdoor Walk calibration has not fixed it.

Has anyone else seen Indoor Walk / treadmill distance drop this much after watchOS 27? Any workaround that actually sticks (GymKit / footpod / treadmill trust, or something else)?

I'd also like a way to edit workout distance after the fact for Indoor Walk — right now I can't correct bad treadmill sessions.

Posted on Nov 1, 2026 2:53 AM

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Answer 1

WheelieNick

Level 9

73,296 points

Nov 1, 2026 7:25 AM in response to shahar243

Hi there

Please try this

. Use GymKit (Direct Treadmill Sync)

If your gym has modern commercial treadmills equipped with GymKit, hold your Apple Watch near the contactless NFC reader on the treadmill console to pair them.
This forces the Apple Watch to pull speed, incline, and distance directly from the treadmill's belt sensors rather than guessing from your wrist.
Check that Detect Gym Equipment is enabled on your watch: Open the Watch app on your iPhone > Workout > toggle on Detect Gym Equipment.

2. Bluetooth Foot Pod (Stryd or Similar)

If you run or walk on indoor treadmills frequently and need precision, a dedicated running foot pod(such as Stryd or other Bluetooth/ANT+ compatible pods) pairs directly to the Apple Watch and measures actual foot movement/stride independently of wrist swing.

3. Adjust How You Move on the Belt

Avoid holding the handrails: Let your arms swing naturally as you would during an outdoor walk. Holding rails cuts wrist motion and causes the watch to undercount.
Check personal health metrics: Double-check that your Height, Weight, and Hand Dominance are accurately entered in the Health app on your iPhone, as the watch uses these baselines for stride estimation.

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