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

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.

Indoor walk distance relies on the calibration from outdoor walks, so it's worth doing a few outdoor walks of 20 minutes or more with GPS after resetting calibration data. Make sure Fitness Tracking and Motion Calibration & Distance are on in Settings > Privacy & Security > Motion & Fitness. Wearing the watch snugly also helps.

I feel I need to chime in here. I just upgraded from the Watch 11 to 12. I'm finding the identical problem. Same type of exercise. Same duration. But now, I can clock an hour of exercise (indoor walking) at my same pace but I am lucky if I get credit for 35 minutes. It's frustrating because my doctors are asking for my numbers and it looks like I am slacking off.

I've recalibrated my watch. Unpaired it and paired it again. No difference. Restarted both devices. Watch 12 and iPhone 18 Pro are both updated to the latest iOS and Watch OS. I made sure Fitness Tracking and Motion Calibration & Distance are on in Settings > Privacy & Security > Motion & Fitness. I am wearing the watch snugly, directly on my skin. No tattoos. No magnetic fields nearby. I do not go to a gym. All the equipment is in my home. All tracking was previously captured by my watch.

Is there anything else I can try before contacting an Apple Genius?

Update on my issue of workouts not tracking correctly on my new Apple Watch 12. I want to share that is has been several days since recalibrating my new Apple Watch. The first couple days were inaccurate. But now, I am seeing numbers that seem to be spot on. It seems it takes several days for the new watch to calculate your step distance, normal heart rate and things like that. I hope the rest of the posters give it a little more time to see if this all works out for you.

How to recalibrate Apple Watch

My treadmill tells me how far I went. Before update treadmill and watch were within 5% of each other. After update 50% off. Does Apple test their software?

Not a good answer! This is an issue with the update and needs to be fixed! I didn't spend $800 on a ultra 3 to have it not work! It worked fine before the update, I didn't change the way I walk! My fitbit never had an issue with this tracking. I wish apple would do a better job testing there updates.

Seriously? I’ve been using trackers for over 15 years. There’s a huge change after an update (BTW this thread was started by someone with the identical problem) and you think I should check the treadmill? We’re talking about a 50% change! I know how fast I walk.

Carol B. wrote:

It's frustrating because my doctors are asking for my numbers and it looks like I am slacking off.

Since the cause of the problem (worse software, better software, space aliens, who knows) has yet to be determined, I think what you're going to need to do for now is explain it to your doctors. I don't know about your situation specifically, but generally, what they want to know is whether you're maintaining or increasing your activity, not the actual number. If you know you're doing exactly the same thing, give them the new number and go from there.

I haven't noticed any statistically significant differences in distance on my watch 12. The metrics I pay attention to the most are time and heart rate. I suspect if you're expending the same amount of time and your heart rate looks similar, your doctors will understand.

Carol B. wrote:

Update on my issue of workouts not tracking correctly on my new Apple Watch 12. I want to share that is has been several days since recalibrating my new Apple Watch. The first couple days were inaccurate. But now, I am seeing numbers that seem to be spot on. It seems it takes several days for the new watch to calculate your step distance, normal heart rate and things like that. I hope the rest of the posters give it a little more time to see if this all works out for you.

That's great news!

Just out of curiosity, how do you know it wasn't the previous watch that was overestimating the distance more often than you thought?

Same watch, same treadmill only difference is the update. Big miss by Apple!

Just because it's the same treadmill doesn't tell you anything. The data on treadmills is notoriously inaccurate.