Mile/Hour to Kilometer/Hour (mph to km/h)
Result
1.609344 Kilometer/Hour
Formula
km/h = mph × 1.609344
1 mph = 1.609344 km/h, and 1 km/h = 0.6213711922 mph.
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
- 20 mph × 1.609344 = 32.18688 km/h
- 30 mph × 1.609344 = 48.28032 km/h
- 60 mph × 1.609344 = 96.56064 km/h
- 70 mph × 1.609344 = 112.65408 km/h
Things to know about mph to km/h
- Multiply by 1.609344 (exact). 70 mph is 112.7 km/h.
- A useful anchor: 50 mph ≈ 80 km/h (exactly 80.47).
Mile/Hour to Kilometer/Hour table
| Mile/Hour (mph) | Kilometer/Hour (km/h) |
|---|---|
| 1 | 1.609344 |
| 2 | 3.218688 |
| 5 | 8.04672 |
| 10 | 16.09344 |
| 20 | 32.18688 |
| 30 | 48.28032 |
| 50 | 80.4672 |
| 60 | 96.56064 |
| 70 | 112.65408 |
| 100 | 160.9344 |
| 1,000 | 1,609.344 |
The units
- Mile/Hour (mph)
- Miles per hour: exactly 0.44704 m/s.
- Kilometer/Hour (km/h)
- Kilometres per hour: 1 km/h = 1/3.6 m/s ≈ 0.27778 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