Instantly convert between Kmph, Mph, Knots, and Mach. Perfect for drivers, pilots, sailors, and physics students.
Speed measurement varies by context. While most countries use Kilometers per hour (km/h) for road traffic, the US and UK use Miles per hour (mph). Aviation and maritime sectors rely on Knots.
Formula: Mph × 1.609. Example: 50 mph ≈ 80 km/h.
Formula: Knots × 1.852. Example: 10 knots ≈ 18.5 km/h.
From Driving to Flying.
Planning a road trip in the US or Europe? Quickly convert speed limits to know if "70" means a relaxed cruise (mph) or a slower highway speed (km/h) to avoid tickets.
Know the limits accurately.
Knots are based on Nautical Miles, which are directly related to degrees of latitude on the Earth's surface. This makes navigation calculations simpler for sailors and pilots.
Yes. The speed of sound (Mach 1) depends on air temperature and pressure. Our calculator uses the standard value at sea level (approx 1235 km/h).