How to use the online speedometer
- Open this page on your phone and press Start speedometer.
- Allow location access when your browser asks. This is required to read GPS.
- Wait a few seconds outdoors for a GPS fix. The dot turns green when accuracy is good.
- Pick MPH, km/h, or knots. Your choice is remembered next time.
- Optional: set a speed alert, or open HUD mode for a big, glanceable display.
How it measures your speed
Your phone’s GPS receiver doesn’t just calculate where you are — it also measures how fast you’re moving, using the tiny Doppler shift in satellite signals. When your browser provides that reading, this speedometer uses it directly. When it doesn’t, the speed is calculated from the distance between consecutive GPS fixes. Readings with poor accuracy are ignored so the distance and maximum speed aren’t thrown off by GPS jumps. Learn more in how a GPS speedometer works.
What you can use it for
- Checking your car’s speedometer. Most car speedometers read a little high. Here’s why.
- Cycling, running, and skating — see your real pace without a bike computer.
- Boats and jet skis — switch to knots.
- Trains, buses, and flights — find out how fast you’re traveling as a passenger.
- Older cars, rentals, and golf carts with a broken or missing speedometer.
Need to convert between units? Use the MPH to km/h converter.
Frequently asked questions
Is this online speedometer free?+
Yes. It's completely free, with no sign-up and no ads. It runs in your browser, and your location is processed on your device — it is never sent to our servers.
How accurate is a GPS speedometer?+
With a clear view of the sky, a phone's GPS speed is usually within about 1–2 mph (2–3 km/h) of your true speed, and it's often more accurate than a car's built-in speedometer. Accuracy drops in tunnels, parking garages, dense cities, and indoors. The ± meters reading under the speed shows the current GPS accuracy.
Why does it show 0 or not change?+
Your browser needs permission to use your location, and GPS needs a clear view of the sky. Allow location access when prompted, step outside or move away from tall buildings, and give it a few seconds to lock on. Very low speeds (under about 1 mph) are shown as 0 to filter out GPS jitter.
Does it work on iPhone and Android?+
Yes. It works in Safari on iPhone and Chrome on Android, as well as most modern desktop browsers. Phones give the best results because they have dedicated GPS hardware; laptops usually estimate location from Wi-Fi and aren't accurate enough for speed.
Does it keep working with the screen off?+
No. Browsers pause location updates when the page is in the background or the screen locks. The page asks your phone to keep the screen awake while it's running. If you want speed tracking and trip recording that keeps working in the background, use the free-to-download iPhone app.
What is HUD mode?+
HUD (head-up display) mode shows your speed in huge digits on a black screen. Turn on Mirror, place your phone flat on the dashboard at night, and the reversed digits reflect the right way round in your windshield.
Can I use it while driving?+
Only if your phone is in a mount and you don't touch it while the car is moving. Set it up before you drive or let a passenger use it. Always follow local laws on phone use while driving — your eyes belong on the road.