Speed Converter

Speed is one of the smaller unit categories in practice — there simply aren't dozens of legitimate named speed units the way there are for length or weight — but the ones that exist span a genuinely huge range of everyday and specialized use: km/h and mph for road speeds and weather reports, knots for anything maritime or aviation-related, Mach for supersonic flight, and the speed of light as an absolute reference point at the top end. This converter includes all the units people realistically need, including a couple of less common ones like feet per minute and the tongue-in-cheek but entirely real furlong per fortnight, a unit physics classes sometimes use specifically because it's an unfamiliar combination that forces you to actually think through the conversion rather than relying on memorized shortcuts.

Enter a value into either field and the other calculates instantly, with a swap button to flip direction. Everything routes through meters per second as the common base, checked against known reference conversions — a knot correctly comes out to 1.852 km/h exactly here, not a rounded approximation.

Dedicated pages for the pairs people look up most — km/h to mph, m/s to mph, knots to mph — are linked below, each preloaded with that specific conversion and a reference table of common values. As with every converter here, this is plain arithmetic running in your browser, with no external service involved and nothing recorded.