Speed converter
Speed measures distance per time. Knots are nautical miles per hour.
Edit either value. Use a decimal point; commas group thousands. Rounding affects display only.
How to convert kilometers per hour to miles per hour
Choose any of the 5 supported units. All conversions within this category share the same calculation engine.
Formula coefficients shown rounded. Calculations use the stored factors before display rounding.
A worked example
For 10 km/h, the result is approximately 6.213711922 mph. 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.
| Kilometers per hour (km/h) | Miles per hour (mph) |
|---|---|
| 1 | 0.6213711922 |
| 2 | 1.242742384 |
| 5 | 3.106855961 |
| 10 | 6.213711922 |
| 20 | 12.42742384 |
| 25 | 15.53427981 |
| 50 | 31.06855961 |
| 100 | 62.13711922 |
| 500 | 310.6855961 |
| 1000 | 621.3711922 |