Stryd is designed to be accurate out of the box without calibration for most runners, but there can be variation between runners and devices. You can always fine-tune Stryd's accuracy to improve it. To understand the exact accuracy of your Stryd, you need to run a known distance. We recommend heading to the track. The detailed procedure: Distance and Calibration
If you are do not have access to a track or prefer to avoid the hassle of the test, you can use the Garmin auto-calibration feature to finetune Stryd calibration. Autocalibration can cause unexpected results when you are in an area with poor GPS reception or are not running on a straight road. Curves and turns will confuse GPS and cause autocalibration to be incorrect. Never leave autocalibration enabled on your Garmin.
1. You must find a road that has a straight segment several kms/miles in length without any elevation change. There should be no multi-story buildings, trees, or other obstructions nearby to optimize the GPS signal. Example:
2. Go to the sensor and accessory menu on your watch and make sure that Stryd is paired as an ANT foot pod only (remove FP-STRYD if present).
3. Check the settings for the foot pod. Make sure the pace and distance are always from Stryd. Enable auto-calibration on your watch.
4. Go to the beginning of the stretch of road that selected in step 1. Let the watch find GPS signal and wait at least 5 minutes.
5. Start recording the activity and run the straight segment only. IT should be a distance at least more than 1 mile or 1.6km. Stop the watch.
6. Go to the sensor and accessory menu on your watch, and change the foot pod settings. Disable auto-calibration on your watch, the watch will retain the calibration factor.