Kilometer per Hour to Mile per Hour Converter
Converts kilometer per hour to mile per hour (km/h to mph) and back. The conversion factor is shown below every result.
How to Convert Kilometer per Hour to Mile per Hour
What Is a Kilometer per Hour?
Kilometers per hour (km/h) is the standard metric unit of speed.
What Is a Mile per Hour?
Based on the statute mile (exactly 1,609.344 meters), miles per hour (mph) is a common speed unit.
Common Kilometer per Hour to Mile per Hour Reference Points
Real-world reference values for quick sanity checks.
| Item | Kilometer per Hour (km/h) | Mile per Hour (approx.) |
|---|---|---|
| US residential speed limit (approx.) | 40 km/h | 24.85 mph |
| Highway speed limit (approx.) | 110 km/h | 68.35 mph |
| Reference values are illustrative approximations for common items, not measured specifications. | ||
Kilometer per Hour to Mile per Hour Conversion Table
| Kilometer per Hour (km/h) | Mile per Hour (mph) |
|---|---|
| 10 km/h | 6.213712 mph |
| 20 km/h | 12.427424 mph |
| 30 km/h | 18.641136 mph |
| 50 km/h | 31.06856 mph |
| 60 km/h | 37.282272 mph |
| 80 km/h | 49.709695 mph |
| 100 km/h | 62.137119 mph |
| 110 km/h | 68.350831 mph |
| 120 km/h | 74.564543 mph |
| 150 km/h | 93.205679 mph |
| Source: NIST SP 811, Appendix B (1 statute mile = 1,609.344 m exactly) | |
Frequently Asked Questions
How do I convert km/h to mph?
Multiply the km/h value by about 0.621371. For example, 100 km/h × 0.621371 = 62.14 mph.
Why is the conversion factor 0.621371?
It comes from the exact definition of the statute mile as 1,609.344 meters. Dividing 1 by 1.609344 gives the km/h-to-mph factor.
What speed limit is 100 km/h in mph?
100 km/h converts to about 62.1 mph, which is why many countries that switched to km/h set highway limits at round metric numbers like 100 or 110 km/h rather than round mph figures.
Related Speed Converters
A good measuring tool marked in both km/h and mph removes the guesswork at the point of use.