Free online car speed checker: see your real GPS ground speed, not your car odometer. More accurate than most built-in speedometers. No app needed.
Tap Start GPS and allow location access
This online car speed check compares what your dashboard says with your true speed from GPS. It is a quick vehicle speed test you can run on any drive, with no app and no equipment.
| Dashboard shows | Typical GPS speed |
|---|---|
| 50 km/h | 46 to 49 km/h |
| 80 km/h | 75 to 78 km/h |
| 100 km/h | 94 to 98 km/h |
If your car reads lower than GPS, or more than about 10 percent higher, check your tyre size and pressure, as worn or non-standard tyres change the reading.
The same speed checker works in a car, van, truck, taxi or auto rickshaw. For two wheelers, use the motorcycle speed test, and to log trip distance, use the GPS odometer.
Not in a car? The vehicle speed test works for bikes, scooters, autos and trucks too.
To run a car speed test, set your phone in a mount before you drive off, tap Start GPS and allow location access. The page reads satellite positions and shows your true road speed in km/h or mph. Most car speedometers are set to read slightly high by design, so a GPS car speed test usually shows a lower, more accurate number.
Your car's built-in speedometer measures wheel rotation, not true ground speed. Tyre wear, incorrect tyre size, and manufacturer calibration all introduce error, and by law it must never read below your true speed, so it typically over-reads by 3–7%. Our online car speed checker uses GPS satellites to measure your actual ground speed with no mechanical error.
A GPS-based checker measures your actual ground speed derived directly from satellite signals, giving you a truer picture of how fast you're moving. It's also useful when driving a rental car, van, or any unfamiliar vehicle where you're unsure if the speedo is calibrated correctly. As a free GPS speedometer for cars, this car speed checker works on any smartphone with no app install required. Riding as a passenger on a coach or city bus? The bus speed test works the same way. And for the other end of the scale, see how fast race cars go.
Always secure your phone in a dashboard or windscreen mount before setting off. Start the GPS tracker while stationary, allow it to acquire a satellite fix (watch the accuracy indicator), then drive. Never interact with the screen while in motion. The tracker will continue running in the background even if your screen dims.
The large number on the gauge is your current car speed. Peak shows the highest speed recorded this session. Avg is your average moving speed. Distance accumulates from the moment tracking starts. All figures from this car speed checker update every 1–2 seconds.
In the EU and UK, vehicle type-approval rules require a speedometer's indicated reading to never fall below true speed, while allowing a margin above it: historically up to roughly 10% plus 4 km/h. Manufacturers build in a buffer to stay safely within that allowance across the tolerance range of mass-produced wheels and tyres, which is why even a brand-new, correctly-specified car typically shows a few km/h more than its true GPS ground speed. The exact permitted margin and enforcement vary somewhat by country, but the direction of the rule, never under-read, free to over-read, is consistent across most major markets. For more on why this creates a permanent gap between your dashboard and a GPS reading, see our guide on GPS speed vs. car speedometer.
GPS-based speed is generally within 1–3 km/h of true speed. Car speedometers legally cannot read below true speed, so they typically over-read by 3–5%. This GPS car speed checker can actually reflect true ground speed more accurately than your dashboard.
Yes, but never hold or operate your phone while driving. Mount it on a dashboard holder and start before moving. Local distracted-driving laws remain your responsibility.
GPS receivers update every 1–2 seconds and signals can vary due to satellite geometry, building reflections, and atmospheric conditions. Slight fluctuations are normal; the average is reliable.
Yes. GPS accuracy doesn't degrade at speed. The checker works reliably from 0 to well over 200 km/h as long as you have a clear view of the sky.
GPS usage does consume battery. For long trips, connect your phone to a car charger. The app keeps the screen active while tracking.
Speedometer regulations require manufacturers to ensure the dashboard never reads below your true speed, but allow it to read higher. Most cars are calibrated to over-read by roughly 3 to 7%, so a GPS reading a few km/h lower than your dashboard is normal, not a fault in either device.
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