How to convert kilometres per hour to miles per hour
One kilometre per hour equals 0.621371 miles per hour, so multiply the number of kilometres per hour by 0.621371:
mph = km/h × 0.621371
km/h = mph ÷ 0.621371 (1 mph = 1.6093 km/h)
Example: 30 km/h → 30 × 0.621371 = 18.6411 mph.
Going the other way, divide by 0.621371, or multiply by 1.6093; the miles per hour to kilometres per hour converter does it for you.
Everyday values
| Kilometres per hour | Miles per hour | For example |
|---|---|---|
| 30 km/h | 18.6411 mph | a city speed limit in many countries |
| 50 km/h | 31.0686 mph | a typical urban limit |
| 100 km/h | 62.1371 mph | a country-road or motorway limit |
| 120 km/h | 74.5645 mph | a motorway limit in many countries |
| 130 km/h | 80.7783 mph | a motorway limit in parts of Europe |
When you need this conversion
Visitors driving abroad need this conversion most. Speed limits of 50, 100 and 120 km/h are about 31, 62 and 75 mph. In running and cycling, speed in km/h converts to pace: 12 km/h is a 5:00 min/km pace, about 8:03 per mile.
Kilometre per hour to mile per hour conversion table
| km/h | mph | km/h | mph |
|---|---|---|---|
| 10 km/h | 6.2137 mph | 90 km/h | 55.9234 mph |
| 20 km/h | 12.4274 mph | 100 km/h | 62.1371 mph |
| 30 km/h | 18.6411 mph | 110 km/h | 68.3508 mph |
| 40 km/h | 24.8548 mph | 120 km/h | 74.5645 mph |
| 50 km/h | 31.0686 mph | 130 km/h | 80.7783 mph |
| 60 km/h | 37.2823 mph | 140 km/h | 86.992 mph |
| 70 km/h | 43.496 mph | 150 km/h | 93.2057 mph |
| 80 km/h | 49.7097 mph |
About the units
- Kilometre per hour (km/h): 1,000 metres per 3,600 seconds.
- Mile per hour (mph): 1 mile per hour, exactly 1.609344 km/h.
Both are units of speed. The conversion factor comes from the exact definitions above, so the calculator is exact; results are only rounded for display (up to six significant digits).
Frequently asked questions
How many miles per hour are in one kilometre per hour?
One kilometre per hour is 0.621371 miles per hour. One mile per hour is 1.6093 kilometres per hour.
How do I convert kilometres per hour to miles per hour?
Multiply the value in kilometres per hour by 0.621371. To go back, divide by 0.621371.
What is 30 km/h in miles per hour?
30 km/h = 18.6411 mph.
What is 50 km/h in miles per hour?
50 km/h = 31.0686 mph.
Sources
- NIST Special Publication 811 (2008), Guide for the Use of the International System of Units (SI), Appendix B: conversion factors.
- NIST Handbook 44 (2024), Appendix C: General tables of units of measurement.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.