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iPhone Health App distance is wrong

Is there a way to fix the Health app being wildly off for distance? On October 21, 2022, the Health app stopped recording distance correctly. I know distance and steps are recorded differently, but stride calculated as distance divided by number of steps should be a reasonable value. Up to October 20, 2022, I was getting a consistent 26-27 inch stride. Since October 21, 2022, it has changed to a 7 inch stride. A plot is attached. I am certain my stride has not changed and I have not changed any settings on my iPhone or in the Health app.

iPhone X

Posted on Oct 25, 2022 2:34 PM

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Posted on Oct 28, 2022 4:59 PM

The Apple Support link was not very helpful and just provided links to setting up my phone (which I know how to do). I did not try hard to find other options, because I solved it today myself.


I went to Health App -> Summary -> Show All Health Data and then scrolled down to the bottom and some app (not me) had changed my height to 2'0" and weight to 72 lbs even though correct height and weight were in Health all along. Next, I clicked on "Height" scrolled down again to "Show Data" and a new entry on 10/21 (when problems started) changed height to 2'0". All other entries in the list have a heart icon and are entries I made in Health app. This new one said it came for "iPhone" (with a phone icon) and did to say what app did it. I also checked my "Data Sources & Access" for both height and weight and both of list ONLY "Heath" for source allowed to update height and weight. Despite these settings some other source was allowed to make the change and that change took precedence of the Health app setting. I don't know how or why. But I deleted them, entered correct ones again to be sure, and now distance is OK.


Other things I learned are:


  1. Some discussions say Health distance is done by GPS while steps is by built-in accelerometer. Apparently, that is not correct. Health app distance is based on steps and stride estimated from height (or calibrated if you have Apple Watch, which I don't).
  2. I have been concerned later that my "Walking Asymmetry" was running 10%-30%, possible indicating slow recovery from recent back surgery. When I fixed my height, the asymmetry dropped to zero so value must depend on height as well.


If your Health app is unreliable, check "Show All Health Data" for unauthorized changes to your height and weight or any other settings.

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Question marked as Top-ranking reply

Oct 28, 2022 4:59 PM in response to Chris_C1

The Apple Support link was not very helpful and just provided links to setting up my phone (which I know how to do). I did not try hard to find other options, because I solved it today myself.


I went to Health App -> Summary -> Show All Health Data and then scrolled down to the bottom and some app (not me) had changed my height to 2'0" and weight to 72 lbs even though correct height and weight were in Health all along. Next, I clicked on "Height" scrolled down again to "Show Data" and a new entry on 10/21 (when problems started) changed height to 2'0". All other entries in the list have a heart icon and are entries I made in Health app. This new one said it came for "iPhone" (with a phone icon) and did to say what app did it. I also checked my "Data Sources & Access" for both height and weight and both of list ONLY "Heath" for source allowed to update height and weight. Despite these settings some other source was allowed to make the change and that change took precedence of the Health app setting. I don't know how or why. But I deleted them, entered correct ones again to be sure, and now distance is OK.


Other things I learned are:


  1. Some discussions say Health distance is done by GPS while steps is by built-in accelerometer. Apparently, that is not correct. Health app distance is based on steps and stride estimated from height (or calibrated if you have Apple Watch, which I don't).
  2. I have been concerned later that my "Walking Asymmetry" was running 10%-30%, possible indicating slow recovery from recent back surgery. When I fixed my height, the asymmetry dropped to zero so value must depend on height as well.


If your Health app is unreliable, check "Show All Health Data" for unauthorized changes to your height and weight or any other settings.

Oct 27, 2022 5:04 PM in response to John Nairn1

Hey there John Nairn1,


Thanks for reaching out to the Apple Support Communities. To get started, do you also use an Apple Watch to track your workouts and activity? If so, you may be able to try calibrating your Apple Watch to get improved accuracy with your distance, pace, and other measurements.


For steps on how to calibrate your Apple Watch, check out this link here: https://support.apple.com/en-us/HT204516


Calibrate your Apple Watch
1. While wearing your Apple Watch, go to a flat, open outdoor area that offers good GPS reception and clear skies. 
2. If you have Apple Watch Series 2 or later, you just need your Apple Watch. If you have Apple Watch Series 1 or earlier, bring your iPhone for GPS. Hold your iPhone in your hand, or wear it on an armband or waistband.
3. Open the Workout app. To start, tap Outdoor Walk or Outdoor Run. To set a goal before starting, tap the ... icon.
4. 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. 


If the above steps don't improve the issue, or if you're not working with an Apple Watch, we'd recommend reaching out to Apple Support directly at this link here: Get Support - Apple


We hope that's able to help.


Take care!

Oct 27, 2022 9:35 PM in response to Chris_V89

I don't have an Apple Watch. I will try the link you sent.


I thought maybe GPS had broken (because I read distance is done by GPS while steps are recorded by accelerometer), but I tested other Apps that use GPS and they all work. It appears only the Health app that is not working.


Maybe calibration would help, but it is not slightly off --- it is off by factor of 4.

iPhone Health App distance is wrong

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