GPS Accuracy Test

Tap Start and your device streams position fixes for up to 30 seconds while this page tracks the reported accuracy of each one — the live figure, the best fix, and the running average, in meters. Under open sky a modern phone should reach 3–8 m; indoors or between tall buildings 20–50 m is normal. Nothing leaves your device — the samples are read, displayed, and discarded.

Why accuracy varies — how GPS actually works

Your browser will ask for location permission — samples are shown on this screen and discarded.

Reading your numbers

The accuracy figure is your device's own uncertainty estimate: a 68% confidence radius, meaning the true position is probably within that many meters — it's honest, not a guarantee. 3–8 m is a good phone under open sky with GPS + Galileo. 10–25 m usually means partial sky view — trees, a window seat, an urban street. 50 m and up means the fix is coming from Wi-Fi or cell towers rather than satellites, which is why the first seconds often start high and tighten as real satellite fixes arrive. Watch the best-fix number: that's what your device can do; the average is what it's doing right now.

Making it better

Open sky beats everything — step away from buildings and out from under roofs. Keep Wi-Fi ON even if unconnected (scanning assists positioning). Give it 30 seconds: cold fixes improve dramatically as more satellites lock. If the dot is wandering hundreds of meters, that's usually a stale IP-based guess, not GPS at all — here's the full diagnosis, and here's why the dot behaves the way it does.

Frequently asked questions

What does the accuracy number actually mean?
It's your device's own uncertainty estimate: a radius in meters within which the true position probably (about 68% confidence) lies. Smaller is better — 5 m means "within a driveway", 50 m means "somewhere on this block".
What's a good result for a phone?
Under open sky, 3–8 m is typical for a modern phone using GPS plus Galileo/GLONASS. 10–25 m suggests a partial sky view; 50 m or more usually means the fix is Wi-Fi or cell-tower based rather than satellite.
Why does accuracy improve while the test runs?
The first fix often comes from Wi-Fi or cell data while the GPS chip is still acquiring satellites. As real satellite locks accumulate over the first 10–30 seconds, the estimate tightens — which is exactly what the falling number is showing you.
Is my position stored or sent anywhere?
No. The samples are read from your browser's geolocation API, shown on screen, and discarded — the test runs entirely on your device and stops the moment you press Stop or leave the page.