Written by Muneeb Rana · Last updated 26 October 2026
Quick answer: These free speed tools run in your browser: an online speedometer, converters for mph, km/h, knots and m/s, and calculators for average speed, speed-distance-time, fuel cost, travel time, running pace, stopping distance and speedometer error. Each explains its formula and links to the guide behind it.
TL;DR
- Online speedometer.
- Converters.
- Calculators.
- Formulas shown.
- No install.
Free speed tools
- Online speedometer: your speed in the browser: A free online speedometer that uses your browser's location to show live speed in MPH or KM/H. No install, no sign-up; works best outdoors.
- How fast am I going right now?: How fast am I going? Check your live speed in MPH or KM/H from your phone's GPS in the browser, with tips for a steady reading and what affects it.
- KMH to MPH converter: Convert kmh to mph instantly: type a speed in km/h and get mph. Includes the exact factor (1.609344), a 10–200 km/h table and a mental shortcut.
- MPH to KMH converter: Convert mph to kmh instantly: multiply by 1.609344. Includes a 5–150 mph table, common US and UK limits in km/h, and a quick mental method.
- Knots to MPH converter: Convert knots to mph and km/h: 1 knot = 1.15078 mph = 1.852 km/h exactly. Table of boat, wind and aircraft speeds, and why sailors use knots.
- MPH to meters per second converter: Convert mph to meters per second: multiply by 0.44704. Includes km/h to m/s, a reference table and why phones report speed in m/s.
- Speed distance time calculator: Free speed distance time calculator: enter any two of speed, distance and time to get the third, in mph, km/h, miles, km, hours and minutes.
- Average speed calculator: Average speed calculator for trips with several legs: add distances and times, include or exclude stops, and see why averaging speeds gives a wrong answer.
- Travel time calculator: Travel time calculator: enter distance and average speed to estimate how long a drive, ride or walk takes, with optional break time and arrival clock.
- Running pace calculator: Running pace calculator: convert finish time to minutes per mile or km, pace to speed in mph or km/h, and predict 5K, 10K and half-marathon times.
- Trip fuel cost calculator: Trip fuel cost calculator: enter distance, fuel economy in mpg or L/100 km and fuel price to estimate what a drive costs, split between passengers.
- Stopping distance calculator: Stopping distance calculator: thinking plus braking distance at any speed, dry or wet, with the UK Highway Code typical figures and the physics behind them.
- Online compass: Free online compass that uses your phone's orientation sensor to show heading in degrees and cardinal points. How to calibrate and why cars confuse it.
- Speedometer error calculator for tyre size changes: Speedometer error calculator: compare old and new tyre sizes to see how much your speedometer and odometer will read high or low after the change.
Formulas
Speed = distance ÷ time; 1 mile = 1.609344 km (NIST).
Get Speedometer PRO on Google Play · Download on the App Store · Set it up before you move; never handle your phone while driving.
Sources
- Unit conversion (NIST Office of Weights and Measures): nist.gov (accessed 26 October 2026)
- Speed (Wikipedia): en.wikipedia.org (accessed 26 October 2026)
FAQ
Is Speedometer PRO free?
Yes, free with ads and optional Premium.
Is GPS speed accurate?
Usually close at steady speed in open sky; tunnels and tall buildings degrade it.
Can I use it while driving?
Set it up before you move and do not handle it while driving.
Which platforms?
iPhone (iOS 15+) and Android.
Do the tools store data?
They run in your browser.