How Fast Am I Going? GPS Speed Readout

Your device's GPS speed in mph, km/h or m/s, read in your browser. It says so when your device reports no speed.

Last updated 9 November 2026

How this is calculated

Your browser's Geolocation API reports speed as coords.speed, in metres per second. It is null when the device cannot provide it. This page converts that number and does nothing else to it.

km/h = m/s × 3.6, because an hour has 3,600 seconds and a kilometre has 1,000 metres.
mph = m/s × 3,600 ÷ 1,609.344, which is about m/s × 2.2369. A mile is 5,280 feet of 0.3048 m, which is exactly 1,609.344 m.
The result is shown to one decimal place. For example, 10 m/s is 22.4 mph, 36.0 km/h or 10.0 m/s.
If the speed is below 0.5 m/s the page shows 0. That threshold is a design choice of this page, not a sourced figure; it stops a parked device from showing a flickering small number.

If your device does not report a speed, the page says "Your device did not report speed". It does not work a speed out from the change in your position, and it shows no range because the API gives no speed accuracy. Knots are not offered.

All of this runs in your browser. Your position and speed are not sent anywhere.

GPS speed and a car speedometer

A device reading and a vehicle's speedometer come from different sources and need not match. This page shows the device's figure only, as the browser supplies it. It is not a legal speed measurement and must not be used as evidence of how fast a vehicle was going.

Warm-up and missing readings

The first reading after pressing Start can take a moment, or arrive without a speed. The page then shows the "did not report speed" message and keeps listening.
Indoors, or with a poor view of the sky, a device may report a position with no speed at all.

If readings keep failing, why your location may be wrong lists what to try. To read other things from the same fix, see elevation and coordinates, or go to the home page.

Safety

Do not look at or operate this page while driving. If you are a passenger, hold the phone steady and let the readings settle for a few seconds.

Where the figures come from

MDN, GeolocationCoordinates (accuracy is in metres at 95% confidence). Checked 9 November 2026.
NOAA National Geodetic Survey, the international foot (0.3048 m). Checked 9 November 2026.
NIST Handbook 44 (2024), Appendix C, general tables of units of measurement. Checked 9 November 2026.