How does the GPS speedometer measure my speed?

After you press "Start speedometer" and allow location, the page receives position updates from your phone. If the device reports a speed, that is used. If not, the speed is worked out from the distance between positions divided by the time between them. The number is smoothed, and anything below 0.5 m/s (1.8 km/h) shows as 0 so a phone lying still does not read a false speed.

Usually within a km/h or two at steady speed in the open, but it lags a second or two when you speed up or slow down, and it is poor indoors, in tunnels and between tall buildings. The dot under the speed shows the position accuracy: green is ±10 m or better, amber is up to ±30 m and red is worse. Positions less accurate than ±100 m are ignored. It is not certified for enforcement or as a replacement for a vehicle speedometer.

What do Max speed, Average (moving) and Trip distance mean?

"Max speed" is the highest smoothed speed since the last reset (it waits for a few positions so one stray reading cannot set it). "Average (moving)" is the trip distance divided by the time you were moving. "Trip distance" adds up the distance covered while moving, in km, miles or nautical miles to match the unit you chose. "Trip time" counts everything since you started. "Reset trip" zeroes all four.

What is HUD view and does the screen stay on?

"HUD view" shows the speed in huge green digits on black. "Mirror" is on by default and flips the digits left to right so they read correctly when reflected in a windscreen; press it to turn mirroring off. While the speedometer runs, the page asks your browser to keep the screen awake, and tells you if the browser cannot. Press Esc or "Exit HUD" to leave HUD view.

Is my location sent or stored, and is it safe to use in a car?

Your position is used in your browser tab to work out speed, then dropped. It is not sent anywhere, saved or shown on a map. Only your chosen unit is remembered on the device. About safety: the driver must never look at or touch a phone while the vehicle is moving. Use the speedometer as a passenger, on foot or when stopped, and follow local law.

Yes. Every tool is free to use, with no account and no credit card. The work runs on your device rather than on our servers, which is what keeps it free to run.

Does it work on mobile?

Yes. It runs in current mobile browsers on iOS and Android, with nothing to install.

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Free GPS Speedometer

See your speed from your phone's GPS in km/h, mph or knots, with top speed, average, trip distance and a mirrored dashboard view.

Runs in your browserNo sign-up, no pop-upsNo login requiredFree foreverkm/h, mph or knotsHUD mirror modeNo map, nothing sent

Do not use this while driving

The driver must never look at or touch a phone while a vehicle is moving. Use this as a passenger, on foot, or when stopped, and obey the law where you are. GPS speed is an estimate and does not replace your vehicle's speedometer or an official speed measurement.

Press "Start speedometer" and allow location access. Speed comes from your phone's GPS. No map is shown and nothing is sent anywhere.

km/h

Your speed appears here after you start.

Max speed

0 km/h

Average (moving)

0 km/h

Trip distance

0.00 km

Trip time

0:00:00

Position accuracy unknown

Good to know

The page uses the speed your device's GPS reports. If there is none, it works speed out from the distance and time between positions and ignores jitter smaller than the position accuracy. Below 0.5 m/s (1.8 km/h) it shows 0.
GPS needs a clear view of the sky. Indoors, in tunnels and between tall buildings the reading is poor or stops.
"Average (moving)" is the trip distance divided by the time spent moving, so stops do not pull it down. "Trip time" counts all the time since you pressed "Start speedometer" or "Reset trip".
Laptops and desktops usually have no GPS, so this works best on a phone or tablet with GPS.
"HUD view" shows the speed large on black. "Mirror" flips it left to right so it reads correctly when reflected in a windscreen. Turn it off to read it normally.

🛰️ Your position is used in this browser tab only to work out speed. It is not sent anywhere, stored or drawn on a map, and nothing goes in the page address. Only your chosen unit is remembered.

How It Works

The page asks the browser for position updates, takes the speed the GPS reports (or works it out from distance over time), and smooths it before showing it.

1
Start the speedometer
Read the safety note, then press "Start speedometer" and allow location access. Wait for the first GPS position.
2
Choose a unit
Pick "km/h", "mph" or "knots". The max, average and trip distance change with it.
3
Use the HUD
Press "HUD view" for large numbers on black. "Mirror" flips them so they read when reflected in a windscreen.
4
Reset or stop
Press "Reset trip" to zero the max, average, distance and time, or "Stop" to end tracking and release the screen.

Your position is used in this browser tab only. Nothing is uploaded, shown on a map or put in the page address.

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