Speed Converter

The Speed Converter is a free online speed converter that switches between kilometers per hour, miles per hour, meters per second, feet per second and knots. It's built for drivers comparing speed limits abroad, runners and cyclists converting a pace or GPS reading between metric and imperial units, pilots and sailors working with knots, and students solving physics problems that mix m/s with km/h. It's equally useful for checking a car's top-speed spec sheet or converting a treadmill's pace display into a more familiar unit.

Typical questions this tool answers instantly include a kmh to mph conversion for a foreign speed-limit sign, a mph to kmh conversion for a car's spec sheet written in imperial units, or a knots to mph conversion for translating a marine weather forecast into something more familiar. Enter a value in any of the five units and the others update immediately, so there's no need to memorize which multiplier goes with which pair or reach for a separate calculator app.

Every conversion is built on exact definitions rather than rounded shortcuts: 1 mile per hour = 0.44704 meters per second exactly (since 1 mile = 1,609.344 m and there are 3,600 seconds in an hour), 1 knot = 1.852 kilometers per hour exactly (a knot is defined as one nautical mile of 1,852 m per hour), and 1 foot per second = 0.3048 meters per second exactly. These exact ratios mean the results hold up for aviation, marine navigation and engineering calculations, not just casual estimates.

All math runs client-side the instant you type, and the swap button flips the direction of any conversion in one click. The tool is free, works offline once loaded, and is fully usable on a phone screen — handy for checking a knot-based wind forecast or a foreign speed limit while you're actually on the move.