Troubleshooting GPS Distance That Is Too High or Too Low
A decision tree for diagnosing trip totals that do not match expectations, from unit errors to missed location samples.
An unexpectedly high or low trip total can come from several different causes. The first step is to identify whether the error is in units, session timing, missing points, GPS drift or the comparison route. Do not assume that a single surprising number proves a specific defect.
If the total is too high
Check whether distance rises while stationary, whether coordinates wander in poor reception and whether the route contains sharp jumps. A filter may be too permissive or the location provider may be noisy. Repeat a short stationary test outdoors and note the reported accuracy. Avoid deleting the session until you have recorded what happened.
If the total is too low
Check whether tracking started late, stopped early or paused when the browser went into the background. Sparse points can cut across turns, and aggressive filtering can omit slow movement. A route planner may also measure a different path from the one actually travelled, so compare like with like.
Check unit and time definitions
Confirm that the total is in the expected unit and that the timer includes the same stops as the comparison tool. A distance display in miles can appear much smaller than the same route in kilometres. If average speed is involved, ensure the time window matches too.
Gather useful evidence
Record device model, browser version, approximate route environment, start/stop timing and whether the page stayed visible. Avoid sharing precise location history publicly. A reproducible short test is more useful to a developer than a statement that the total 'looks wrong' without context.
Frequently asked questions
What should I check first?
Units, start/stop timing, fresh updates and whether the distance changes while stationary.
Can one formula fix every distance mismatch?
No. The cause may be missing or noisy input, not just the calculation formula.
Technical references
These references explain the underlying browser and positioning concepts. They do not imply endorsement of this website.