mph, km/h, knots: drive, sail and run informed anywhere in the world.
Renting a car abroad means meeting speed limits in a unit you don't think in — and the numbers are deceptively similar: 100 km/h is 62 mph, so driving "100" in the US means something 60% faster than in Europe. Boats and planes add a third unit, the knot, which matches neither.
Below, road-speed converters for the countries you'll drive in, plus nautical and scientific speeds, each with the mental shortcut that keeps you legal and calm at the wheel.
These converters cover the speeds you actually meet: highway limits in mph and km/h, sailing and aviation knots, and the m/s that physics teachers love. Each page pairs the exact factor with road-realistic tables and the mental shortcut that keeps you driving legally abroad — because at "100", the unit makes a 60% difference.
Are these converters really free? Yes — unlimited, no account, no paywall. CalculUnits is funded by non-intrusive ads only.
How accurate are the results? Every conversion uses the exact official factor from SI and NIST references, shown on each page so you can verify the math yourself.
Do my values leave my device? No — all calculations run in your browser. Nothing you type is ever sent anywhere.