How to use
- Type a speed in Value.
- Pick the From and To units, or tap a popular conversion.
- Read the answer. The exact factor is shown under it.
How the conversion works
Every unit has an exact size in meters per second. The converter turns your value into m/s, then into the unit you want:
result = value × (m/s in "from" unit) ÷ (m/s in "to" unit)
| Unit | Exact size |
|---|---|
| 1 mph | 1.609344 km/h = 0.44704 m/s |
| 1 km/h | 1/3.6 m/s ≈ 0.6214 mph |
| 1 knot | 1 nautical mile per hour = 1.852 km/h |
| 1 m/s | 3.6 km/h |
| 1 ft/s | 0.3048 m/s |
A mile is exactly 1,609.344 m and a nautical mile exactly 1,852 m, so these factors involve no rounding.
Examples
- 70 mph to km/h: 70 × 1.609344 = 112.65 km/h
- 100 km/h to mph: 100 ÷ 1.609344 = 62.14 mph
- 20 knots to mph: 23.02 mph
- 10 m/s to km/h: 10 × 3.6 = 36 km/h
Conversion charts
| mph | km/h |
|---|---|
| 20 mph | 32.2 km/h |
| 30 mph | 48.3 km/h |
| 40 mph | 64.4 km/h |
| 50 mph | 80.5 km/h |
| 60 mph | 96.6 km/h |
| 70 mph | 112.7 km/h |
| 80 mph | 128.7 km/h |
| km/h | mph |
|---|---|
| 30 km/h | 18.6 mph |
| 50 km/h | 31.1 mph |
| 80 km/h | 49.7 mph |
| 100 km/h | 62.1 mph |
| 110 km/h | 68.4 mph |
| 120 km/h | 74.6 mph |
| 130 km/h | 80.8 mph |
| Knots | mph | km/h |
|---|---|---|
| 5 kn | 5.8 | 9.3 |
| 10 kn | 11.5 | 18.5 |
| 20 kn | 23 | 37 |
| 30 kn | 34.5 | 55.6 |
| 50 kn | 57.5 | 92.6 |
| 100 kn | 115.1 | 185.2 |
More detail: knots and Mach
- Knots are used at sea and in the air. A nautical mile is tied to latitude on navigation charts, so speeds in knots match chart distances.
- Mach isn’t a fixed unit. It compares a speed with the local speed of sound, which drops as air gets colder. NASA puts it at about 761 mph at sea level on a standard day.
- Spellings: kph, kmph and km/h all mean kilometers per hour.
Need the distance itself in miles or kilometers? Use the length converter.