Apple's calibration article is the fix for distance and route drift. Settings on the iPhone must allow it first: Privacy and Security, Location Services on, then System Services, and Motion Calibration and Distance on. Then wear the watch on a flat, open outdoor area with good GPS reception and clear sky, open Workout, choose Outdoor Walk or Outdoor Run, and walk or run at your normal pace for about 20 minutes. If you use different speeds, calibrate for 20 minutes at each.
You can do it over several outdoor sessions. Calibration teaches the accelerometer your stride at different speeds, which matters when GPS is limited. Apple's footnote adds which watch uses its own GPS: an Ultra and later, Series 8 and later and SE 2 use the built-in GPS even when the iPhone is nearby, while older watches use the iPhone's GPS when available to save battery. To start over, use the Watch app, Privacy, Reset Fitness Calibration Data.
Differential
Likely causes of “Apple Watch GPS distance or route is inaccurate”, and how to tell them apart
- 1
Location Services or Motion Calibration is off on the iPhone
What separates it Distance and pace are wildly off from the first minute
How to confirm Turn on Location Services and Motion Calibration and Distance in the iPhone's Settings
- 2
The watch was never calibrated
What separates it The distance is consistently high or low because the watch was never calibrated
How to confirm Do the 20 minute outdoor calibration, and compare the distance
- 3
Poor sky view
What separates it Route jumps in tunnels, between buildings or under trees
How to confirm Test in an open area and compare, with a known route
- 4
An older watch is using the iPhone's GPS
What separates it The route drops when you leave the phone behind because an older watch is using the iPhone's GPS
How to confirm Apple says older models use the iPhone's GPS when available; take the phone or use a newer model
- 5
Wrong workout type
What separates it The indoor and outdoor distances differ because of the wrong workout type
How to confirm Choose Outdoor Run or Outdoor Walk for outdoor tracking
- 6
Bad calibration data
What separates it The distance stays wrong after calibrating because of bad calibration data
How to confirm Reset Fitness Calibration Data in the Watch app and calibrate again
Before you touch a setting
Record this first — changing settings destroys the evidence
- The model number, watchOS version and the workout type
- What went wrong: distance, pace, route line, or no GPS at all
- Where it happened and how open the sky view was
- Whether the iPhone was with you and whether Location Services and Motion Calibration and Distance are on
Try in this order
0 of 7 completedTurn the iPhone settings on
ReversibleIn Settings, Privacy and Security, Location Services on, then System Services, Motion Calibration and Distance on.
Go outdoors
ReversibleGo outdoors, and find a flat open area with good GPS reception and a clear sky.
Start an outdoor workout
ReversibleStart an outdoor workout, by tapping Outdoor Walk or Outdoor Run in Workout, and then test again to see whether it helped.
Walk or run for 20 minutes
ReversibleWalk or run for 20 minutes, using your normal pace, or 20 minutes at each pace you use.
Repeat over sessions
ReversibleRepeat over sessions, since calibration can be built up across several outdoor workouts, and then test again to see whether it helped.
Reset if needed
ReversibleReset if needed, by opening the Watch app, My Watch, Privacy, Reset Fitness Calibration Data, and then calibrating again.
Restart and recheck
ReversibleRestart the watch and iPhone and check a short outdoor walk against a known distance.
Model-specific
What is true of this model and not of its siblings
- GPS by model
- Apple's tech specs: L1 GPS, GLONASS, Galileo, QZSS and BeiDou on the Series 8; L1 GPS, GNSS, Galileo and QZSS on the SE 2; an Ultra 2 with GPS antennas and an always-on altimeter.
- Who uses the iPhone's GPS
- Per Apple's footnote, the Ultra and later, Series 8 and later and SE 2 use the built-in GPS even with the iPhone nearby; the Series 7, 6 and earlier use the iPhone's GPS when it is available.
- Repair cost
- Calibrating costs nothing. A watch whose GPS never locks outdoors after a restart is a hardware fault; Apple's out-of-warranty battery service is $99 and broader repairs ran from $199 for an SE 2 to $499 for an Ultra at launch, per MacRumors.
- Other models this page answers
- These steps also fit models Apple Watch Ultra, Apple Watch Series 9, Apple Watch Series 8, Apple Watch Series 7, Apple Watch Series 6.
Stop boundary
When this stops being a self-service repair
- !If GPS never locks in an open field after calibration and a restart, book Apple service
- !If only distance is off, redo the calibration before blaming the hardware
- !If the route is wrong only under trees or in cities, that is a signal issue, not a fault
Evidence ledger
Sources behind this answer
Location Services, Motion Calibration and Distance, the 20-minute outdoor calibration and the GPS footnote.
L1 GPS, GLONASS, Galileo, QZSS and BeiDou.
GPS antennas and always-on altimeter.
Workout type and fit.
The Apple Watch line and its generations.
Exact questions
Common questions
Why is my distance off?+
Usually calibration or Location Services. Follow Apple's 20-minute outdoor calibration.
Do I need my iPhone for GPS?+
Apple says the Ultra and later, Series 8 and later and SE 2 use the built-in GPS even when the iPhone is nearby; older models use the iPhone's GPS when it is available.
How long does calibration take?+
About 20 minutes of walking or running at your normal pace, which can be spread over several outdoor sessions.
Which satellite systems does it use?+
Apple's Series 8 tech spec lists L1 GPS, GLONASS, Galileo, QZSS and BeiDou; the SE 2 lists L1 GPS, GNSS, Galileo and QZSS.
Does calibration help indoors?+
It helps distance and calories when GPS is limited, by learning your stride at different speeds.
Why does the route jump?+
Tall buildings, tunnels and tree cover blur the signal. Test in the open.
How do I reset calibration?+
In the Watch app, My Watch, Privacy, Reset Fitness Calibration Data.
Does the Ultra track better?+
Apple lists dual-frequency GPS on the Ultra 2, which helps in cities and valleys, but calibration and sky view still matter.
Should I use Indoor Walk outside?+
No. Indoor workouts use the accelerometer and not GPS, so the route will be missing.