Speed Converter
Convert speed between miles per hour, kilometers per hour, meters per second, feet per second, knots, Mach and the speed of light.
Change the values and press Calculate to work out your own figures.
Enter a speed, choose its unit and the unit you want. The answer is exact until it is shown, and the same value appears in every other unit.
Show the working
- 1 mph = 1.609344 km/h
- 60 × 1.609344 = 96.56064 km/h
How to use it
Type a speed, choose the unit it is in and the unit you want, then press Calculate. You can type decimals, fractions such as 3/8, mixed numbers such as 1 1/2, very large or small numbers such as 2.5e6, and simple sums such as 2*3. Swap exchanges the two units.
The answer is worked out with exact fractions and only rounded for display, to 12 significant figures. Below it you get the same value in every other unit on the list, and Show the working gives the factor that was used.
Key definitions
1 mph = 1.609344 km/h 1 knot = 1.852 km/h 1 m/s = 3.6 km/h
Mach numbers
Mach 1 is the speed of sound in the air around the aircraft, which falls as the air gets colder: about 343 m/s at 20 °C, 340 m/s at 15 °C and 295 m/s at cruising altitude. This converter uses 343 m/s, so treat its Mach figures as sea-level approximations.
Questions
How fast is 60 mph in km/h?
96.56064 km/h.
How many km/h is one knot?
Exactly 1.852 km/h, one nautical mile per hour.
Formulas
result = (value × f(from) + o(from) − o(to)) ÷ f(to)
Sources
Limitations
- Only the units listed are supported here; other speed units arrive with later M4 slices.