Kilometer/Hour to Mile/Hour (km/h to mph)
Result
0.6213711922 Mile/Hour
Formula
mph = km/h × 0.6213711922
1 km/h = 0.6213711922 mph, and 1 mph = 1.609344 km/h.
Speed units are a length divided by a time: 1 km/h = 1/3.6 m/s, 1 mph = 0.44704 m/s exactly, and 1 knot = 1 nautical mile per hour = 1,852/3,600 m/s.
Worked examples
- 30 km/h × 0.6213711922 = 18.641136 mph
- 50 km/h × 0.6213711922 = 31.06856 mph
- 100 km/h × 0.6213711922 = 62.137119 mph
- 120 km/h × 0.6213711922 = 74.564543 mph
Things to know about km/h to mph
- Multiply by 0.621371. 100 km/h, a common motorway limit, is 62.1 mph.
- Most speedometers sold in mph countries also show km/h on an inner scale.
Kilometer/Hour to Mile/Hour table
| Kilometer/Hour (km/h) | Mile/Hour (mph) |
|---|---|
| 1 | 0.62137119 |
| 2 | 1.2427424 |
| 5 | 3.106856 |
| 10 | 6.2137119 |
| 20 | 12.427424 |
| 30 | 18.641136 |
| 50 | 31.06856 |
| 100 | 62.137119 |
| 120 | 74.564543 |
| 1,000 | 621.37119 |
The units
- Kilometer/Hour (km/h)
- Kilometres per hour: 1 km/h = 1/3.6 m/s ≈ 0.27778 m/s.
- Mile/Hour (mph)
- Miles per hour: exactly 0.44704 m/s.
Sources for these factors
- Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
- Handbook 44 (2024), Appendix C: General Tables of Units of Measurement — NIST
Last reviewed against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy