km/h to mph
Kilometer per hour to mile per hour
NIST SP 811 factors
Speed conversions
Speed conversions between kilometers per hour, miles per hour, and meters per second. Because the mile is exactly 1,609.344 meters, the km/h ↔ mph factor is exact: 1 mph = 1.609344 km/h.
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mph to km/h
Mile per hour to kilometer per hour
Reference
All speed units
Factors trace back to NIST SP 811
| Unit | Symbol | Factor |
|---|---|---|
| Meter per second | m/s | SI derived unit |
| Kilometer per hour | km/h | 1 km/h = 1/3.6 m/s (exact) |
| Mile per hour | mph | 1 mph = 0.44704 m/s (exact) |
Factors are exact definitions; results are
rounded only for display.
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