About the GPS speedometer
This online speedometer uses your device's built-in GPS to measure how fast you are actually moving and shows it on an analog dial and a large digital readout. You can switch between km/h, mph, m/s and knots, and it tracks your top and average speed. It works for a car, bike, bus, train, boat or run — anything that moves. Everything is processed on your device; nothing is uploaded or stored.
How GPS Speedometer works
How it works
When you press Start, the page asks for location permission and then watches your GPS position. Modern phones report speed directly from the GPS chip; if that value is not available, the tool calculates speed from how far your position moved between updates (using the great-circle distance) divided by the time elapsed. Tiny movements while standing still are ignored so the reading does not drift.
Getting an accurate reading
- Open it on a phone and allow location access.
- Use it outdoors with a clear view of the sky — GPS is weak indoors.
- Give it a few seconds to get a fix; the accuracy figure (in metres) shows how good the signal is.
GPS speed is usually accurate to within a few km/h once you have a solid fix, and is often closer to your true ground speed than a car's built-in speedometer, which tends to read slightly high.
Common uses
- Measure your speed by GPS
- Check a car speedometer accuracy
- See your cycling or running speed
- Track boat or sailing speed in knots
- Show speed in km/h, mph or m/s
- Find your top speed on a trip
- See your average speed
- Use as a backup vehicle speedometer