Every smartphone already has the hardware to be a precise speedometer. The challenge is choosing among hundreds of apps that want to display the number. Most have ads. Many overcharge for features the phone provides for free. A few are excellent. Here is an honest comparison of the options that actually deserve your attention, organized by what you want them for.
What matters in a speedometer app (and what doesn't)
A speedometer app shows a number derived from the GPS chip in your phone. The accuracy of that number depends on the hardware and the satellites, not the app. Every iOS speedometer reads from Core Location and gets the same reading; every Android one reads from FusedLocationProvider and gets the same reading. The difference between apps is what they do around that number.
Things that actually matter:
- Ads. A free app with a banner ad blocking part of the dial is annoying when you are driving. A paid version, or a no-ad free option, is worth the small premium.
- Battery efficiency. GPS is power-hungry. Well-built apps pause GPS reading when the screen is off; poorly-built ones drain your phone in 90 minutes.
- Trip recording. If you want to review where you went, your top speed, your average pace, you need an app that stores trips. Browsers cannot do this.
- HUD (heads-up display) mode. Inverts the screen so the number reflects readable off your windshield at night. Niche but very useful for night driving.
- Speed alarm. Vibrates or chimes when you exceed a threshold you set. Helpful in countries with strict limits.
- Unit toggle. Some apps insist on a system default. The good ones let you switch mph to kph and back with one tap.
Things that do not matter for speed accuracy:
- App price (free and paid use the same GPS chip)
- App size (a 5 MB app and a 200 MB app give the same reading)
- Brand (a small-developer app and a billion-dollar one read the same satellites)
Best free, no install: browser speedometer
If you only need a speedometer for the next 20 minutes, the cheapest and fastest option is to open one in your browser. gpsspeedometer.io works in Safari, Chrome, Firefox, and any modern mobile browser. Tap "Begin", grant location permission once, and you have a live speedometer with MPH and KPH toggle. Nothing is downloaded, nothing is installed, and the page never uploads your location. The same browser API (Geolocation) is used by Google Maps, Apple Maps, and every native speedometer app — accuracy is identical to a paid app.
The trade-off: you have to keep the browser tab open. Your phone's auto-lock will pause it. There is no trip recording, no history, no offline map. For a one-off measurement (verifying your car dashboard, checking a treadmill, settling a bet), this is perfect. For ongoing use, install something.
Best free iOS app: our GPS Speedometer
Full disclosure, this is our own app. We built the GPS Speedometer iOS app because we use it ourselves, and we wanted a free option that did not come loaded with ads. It includes trip recording, HUD mode, ghost-pace racing against your previous best, live maps, and speed-over-time charts. There are no ads, no account, no paywall. We make nothing from it directly; it is the companion to the browser tool and the iOS app store is the channel we use to reach drivers and runners who want a permanent installation.
If you prefer a non-our-product option: Speedometer & GPS by Smart Tools Co (free with banner ads, decent feature set) and Speedometer 55 Pro (one-time paid, no ads, extensive customization) are both well-rated and widely used.
Best free Android app
GPS Speedometer and Odometer by Pyxis (free with non-intrusive ads, simple interface) is the most-downloaded Android option and works well for daily driving. Ulysse Speedometer is a long-standing favorite among Android drivers with extensive customization, a paid version that removes ads, and one of the best HUD implementations available.
Best for specialized use cases
Boating: Knots, current, and tide data matter alongside speed. Boat Speedometer and Navionics Boating are the standard picks. For a quick conversion, our knots to mph converter covers the basic unit translation.
Aviation: Knots in IAS (indicated airspeed) vs GPS ground speed are different concepts; pilots use Garmin Pilot or ForeFlight, which integrate with airframe avionics. A phone speedometer alone is supplementary, not primary.
Running: Pace matters more than speed for runners. Strava and Garmin Connect are industry standards, with built-in pace alerts and route tracking. For a quick pace-to-speed conversion, our pace converter handles min/km, min/mile, mph, and kph in one screen.
Motorsport / track days: RaceChrono and Harry's LapTimer add lap timing and split analysis. The phone GPS is enough for casual track logging; serious lap times need a dedicated GPS unit at 10 Hz or higher.
How to choose
Ask three questions:
- Will I use this once or daily? Once means browser. Daily means install.
- Do I want my trips saved? Yes means a native app. No means anything works.
- Am I OK with ads? No means paid, or our free-no-ads app, or a browser tool.
Whatever you pick, verify it against the real ground truth once. The best way is our 10-minute car speed test, which walks through a cruise-control comparison at three speeds. If the app shows the same number as a GPS-based test, you can trust it. If it consistently disagrees, switch.
The takeaway
The "best" speedometer app depends on your context. For a quick check, the browser is unbeatable. For daily driving, a native app with trip recording earns its keep. For motorsport, sailing, or aviation, get the specialized tool. In every case, the speed reading itself is the same number from the same chip — what you are paying for (or not) is the interface and the extras around it.
To try the no-install option right now, open the browser speedometer on your phone. To compare how iOS does this natively, see our 4 ways to see speed on iOS guide.