Speed converter (km/h, m/s, mph, knots)
Convert speeds between km/h, m/s, miles per hour, knots, feet per second and Mach, with all units at once.
How to useSpeed unit conversion
To go from km/h to m/s, divide by 3.6. Mach 1 is taken at sea level at 15 °C (340.29 m/s).
Available in: 
Speed converter (km/h, m/s, mph, knots): what it is for
Type the speed and choose the unit to convert between meters per second, kilometers per hour, miles per hour, knots, feet per second, centimeters per second, Mach and kilometers per second. To go from mph to km/h, multiply by 1.609.
The conversion runs in your browser, using the official conversion factor for each unit.
How to use
- Type the value.
- Choose the unit.
- Copy the conversion.
When to use it
- Solving kinematics exercises.
- Converting car speeds between mph and km/h.
- Understanding boat and aircraft speeds in knots.
Frequently asked questions
How do I convert km/h to m/s?
Divide by 3.6. For example, 72 km/h ÷ 3.6 = 20 m/s. To go the other way, multiply by 3.6.
How much is a knot?
A knot is one nautical mile (1,852 m) per hour, or 1.852 km/h. It is the unit used in sailing and aviation.
What is Mach?
It is the ratio between a speed and the speed of sound. At sea level, at 15 °C, Mach 1 is about 1,225 km/h (761 mph). At altitude the value drops because the air is colder.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.