Speed converter
Speeds share the same time unit, so converting a speed is really converting a distance. 1 mph is exactly 1.609 344 km/h and 1 knot is exactly 1.852 km/h.
100 km/h = 62.13711922 mph
Formula: mph = km/h ÷ 1.609344
100 km/h in every speed unit
- metre per second
- mile per hour
- knot
- foot per second
Popular speed conversions
How it works
Same hour, different miles
The hour never changes, so converting a speed is just converting the distance. A knot is faster than a mph only because a nautical mile (1852 m, based on one minute of latitude) is longer than a land mile (1609.344 m).
- 100 km/h1000 m per hour
- 62.137 mpha mile is 1.609 344 km, so divide by that
- 53.996 knotsa nautical mile is 1.852 km, so divide by that
- 27.778 m/s1000 m ÷ 3600 s = divide by 3.6
- 91.134 ft/sm/s ÷ 0.3048
Every speed unit, defined
Each unit expressed in metres per second, with its exact definition and source.
| Unit | In m/s | Definition | Source |
|---|---|---|---|
| metre per second (m/s) | 1 | SI coherent unit | BIPM SI Brochure |
| kilometre per hour (km/h) | 0.277777777777778 | 1 km/h = 1000 m ÷ 3600 s = 1/3.6 m/s | BIPM SI Brochure |
| mile per hour (mph) | 0.44704 | 1 mph = 1609.344 m ÷ 3600 s = 0.447 04 m/s | NIST SP 811, App. B (1959 yard & pound agreement) |
| knot (kn) | 0.514444444444444 | 1 kn = 1 nautical mile per hour = 1852/3600 m/s | NIST SP 811 |
| foot per second (ft/s) | 0.3048 | 1 ft/s = 0.3048 m/s | NIST SP 811, App. B (1959 yard & pound agreement) |
Questions
How do I convert mph to km/h?
Multiply by 1.609 344. 60 mph = 96.56 km/h.
How do I convert km/h to mph?
Divide by 1.609 344, or multiply by about 0.621 371. 100 km/h = 62.14 mph.
What is a knot?
One nautical mile per hour: exactly 1.852 km/h, or about 1.150 78 mph.
How do I get m/s from km/h?
Divide by 3.6, because 1000 m ÷ 3600 s = 1/3.6.