Speed Conversion
km/h ↔ mph ↔ m/s ↔ knots.
What does Speed Conversion mean?
Speed conversion translates a velocity measurement from one unit to another. Different countries and industries use different speed units — kilometers per hour for road travel in most of the world, miles per hour in the US and UK, meters per second in physics, and knots in aviation and maritime navigation. Converting between them is essential for travel planning, engineering, and scientific work.
How to calculate Speed Conversion
All speed conversions work through a common base unit — meters per second (m/s). First convert the input to m/s, then from m/s to the target unit. Key conversion factors: 1 km/h = 0.2778 m/s, 1 mph = 0.4470 m/s, 1 knot = 0.5144 m/s, 1 ft/s = 0.3048 m/s. For example, 100 km/h = 100 × 0.2778 m/s = 27.78 m/s = 27.78 / 0.4470 mph ≈ 62.14 mph.
FAQ
A knot is one nautical mile per hour. Nautical miles are based on the geometry of the Earth — one nautical mile equals one minute of latitude. This makes navigation calculations much simpler when working with charts and coordinates.
At sea level and 20 °C, the speed of sound is approximately 343 m/s, 1,235 km/h, 767 mph, or 667 knots. This is often referred to as Mach 1.
A quick mental approximation: divide km/h by 1.6. For example, 100 km/h ÷ 1.6 ≈ 62.5 mph. The exact factor is 1.60934, so this gives a very close estimate.
Related calculators
- Unit Conversion— Change measurement units.
- Temperature Conversion— Celsius ↔ Fahrenheit ↔ Kelvin.
- Area Conversion— m² ↔ ft² ↔ acres ↔ hectares.