How this conversion works
Speed is distance divided by time, so each speed unit's factor comes from its length and time units. One mile per hour is 1,609.344 m in 3,600 s, which is exactly 0.44704 m/s.
A knot is one nautical mile (1,852 m) per hour. Kilometers per hour divide by 3.6 to give meters per second.
Formula: result = value × (base units per source unit) ÷ (base units per target unit)
Where this conversion is used
- Driving abroad where limits are posted in km/h or mph.
- Wind speed and boat speed in knots.
- Running pace planning and treadmill speeds.
- Physics problems that require meters per second.
Worked example: 65 mph to km/h
- One mile is 1.609344 km, so 1 mph = 1.609344 km/h.
- 65 × 1.609344 = 104.60736 km/h.
- Rounded: about 104.6 km/h.
Unit definitions
| Unit | In meters per second | Note |
|---|---|---|
| Kilometer per hour (km/h) | 0.2777777778 | |
| Mile per hour (mph) | 0.44704 | |
| Meter per second (m/s) | 1 | |
| Foot per second (ft/s) | 0.3048 | |
| Knot (kn) | 0.5144444444 | One nautical mile (1,852 m) per hour. |
Kilometers per hour to miles per hour
| Kilometer per hour (km/h) | Mile per hour (mph) |
|---|---|
| 10 | 6.2137 |
| 30 | 18.6411 |
| 50 | 31.0686 |
| 60 | 37.2823 |
| 80 | 49.7097 |
| 90 | 55.9234 |
| 100 | 62.1371 |
| 110 | 68.3508 |
| 120 | 74.5645 |
| 130 | 80.7783 |
Miles per hour to kilometers per hour
| Mile per hour (mph) | Kilometer per hour (km/h) |
|---|---|
| 10 | 16.0934 |
| 20 | 32.1869 |
| 25 | 40.2336 |
| 30 | 48.2803 |
| 45 | 72.4205 |
| 55 | 88.5139 |
| 65 | 104.6074 |
| 70 | 112.6541 |
| 75 | 120.7008 |
| 80 | 128.7475 |
Precision and sources
Results are calculated from the definitions above and rounded to 12 significant digits; the converter shows up to eight decimal places and the tables four. Reference: NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B.
Frequently asked questions
How do I convert km/h to m/s?
Divide by 3.6. For example, 90 km/h ÷ 3.6 = 25 m/s.
Is a knot faster than a mile per hour?
Yes. One knot is about 1.15078 mph, because a nautical mile is longer than a statute mile.