mph to km/h
Compare speed limits and vehicle speeds across mile- and kilometer-based systems.
Edit either value. Use a decimal point; commas group thousands. Rounding affects display only.
How to convert miles per hour to kilometers per hour
Compare speed limits and vehicle speeds across mile- and kilometer-based systems.
Formula coefficients shown rounded. Calculations use the stored factors before display rounding.
A worked example
For 10 mph, the result is approximately 16.09344 km/h. To go the other way, edit the result above or swap the units.
Speed measures distance per time. Knots are nautical miles per hour.
Where the numbers come from
Factors follow NIST conversion references and documented unit definitions. Read our accuracy and rounding notes.
The table and method describe this page’s original pair. Changing units above does not change this reference section.
| Miles per hour (mph) | Kilometers per hour (km/h) |
|---|---|
| 1 | 1.609344 |
| 2 | 3.218688 |
| 5 | 8.04672 |
| 10 | 16.09344 |
| 20 | 32.18688 |
| 25 | 40.2336 |
| 50 | 80.4672 |
| 100 | 160.9344 |
| 500 | 804.672 |
| 1000 | 1609.344 |