About speed units
This speed converter changes a speed between kilometres per hour, miles per hour, knots, metres per second and feet per second. Type a value into any box and every other unit updates instantly. It runs in your browser; nothing is uploaded.
How Speed Converter works
The conversion factors
Every unit is converted through metres per second: 1 km/h = 0.27778 m/s, 1 mph = 0.44704 m/s, 1 knot = 0.51444 m/s and 1 ft/s = 0.3048 m/s. To convert between any two, the tool turns your value into m/s and back out into the others.
Worked example
100 km/h ÷ 3.6 = 27.78 m/s. Multiply by 2.23694 to get 62.1 mph, by 1.94384 to get 54.0 knots, and that 27.78 m/s is about 91.1 ft/s.
Want to measure your real speed instead of converting? Use the GPS speedometer.
Common uses
- Convert km/h to mph
- Convert mph to km/h
- Convert knots to km/h or mph
- Convert m/s to km/h
- Convert feet per second
- Compare speeds in different units
- Check a speed limit in another unit
- Convert wind or boat speed
Frequently asked questions
How do I convert km/h to mph?
Divide km/h by 1.60934, or just type the value here and read the mph box. 100 km/h is about 62.1 mph.
What is a knot in km/h?
One knot is 1.852 km/h (one nautical mile per hour).
How many m/s is 1 km/h?
0.27778 m/s — divide km/h by 3.6.
Does it update all units at once?
Yes — type in any field and the other four convert instantly.
Is it accurate?
Yes — it uses exact internationally-defined conversion factors.
Is it free?
Yes, completely free with no sign-up.