Convert Mile per Hour to Kilometer per Hour
1 mile per hour = 1.609344 kilometers per hour (mph to km/h).
The mile per hour (mph) and the kilometer per hour (km/h) both measure speed. A mile per hour is larger than a kilometer per hour — one mile per hour contains 1.60934 kilometers per hour. Going the other way, one kilometer per hour is 0.621371 miles per hour. The converter above does this in real time, and the reference chart lists the values that come up most often.
1 mph = 1.609344 km/h
How to convert Miles per Hour to Kilometers per Hour
Multiply the mile per hour value by 1.60934 to get kilometers per hour.
Example: 10 miles per hour = 16.0934 kilometers per hour.
One mile per hour equals exactly 1.609344 kilometers per hour — the exactness follows from the 1959 definition of the international mile (1609.344 m). To convert mph to km/h, multiply by 1.609344. A UK motorway limit of 70 mph is 112.65 km/h; an American 65 mph interstate limit is 104.61 km/h.
Car speedometers sold in countries that use mph (US, UK, Cayman Islands, a handful of others) must by law also display km/h — usually as a secondary ring or a smaller inner scale. Rental car drivers from metric countries and visitors hiring UK cars frequently misread speeds: seeing '60' on a British road sign and assuming km/h would mean driving at roughly 37 mph, far too slow for a dual carriageway.
Racing and motorsport add precision to the conversion. The top speed of a Formula 1 car during a qualifying lap may be quoted as 220 mph (354 km/h) or 350 km/h (217.5 mph) depending on whether the broadcast is aimed at a US or international audience. A few km/h difference can matter for drag modelling, so teams work with exact SI values and convert for broadcast rather than the reverse.
A rough mental shortcut: multiply mph by 1.6 to estimate km/h. That gives 0.6% too few km/h (since the exact factor is 1.609344), which is close enough for reading road signs but not for calibrating a GPS device or comparing speed-camera tolerances.
Mile per Hour to Kilometer per Hour Conversion Chart
| Miles per Hour | Kilometers per Hour |
|---|---|
| 1 mph | 1.609344 km/h |
| 2 mph | 3.218688 km/h |
| 3 mph | 4.828032 km/h |
| 5 mph | 8.04672 km/h |
| 10 mph | 16.09344 km/h |
| 20 mph | 32.18688 km/h |
| 25 mph | 40.2336 km/h |
| 50 mph | 80.4672 km/h |
| 100 mph | 160.9344 km/h |
| 1000 mph | 1,609.344 km/h |
Frequently Asked Questions
- How many kilometers per hour are in a mile per hour?
- There are 1.609344 kilometers per hour in 1 mile per hour.
- How do you convert miles per hour to kilometers per hour?
- Multiply the mile per hour value by 1.60934 to get kilometers per hour.
- What is 5 miles per hour in kilometers per hour?
- 5 miles per hour equals 8.04672 kilometers per hour.
- What is 100 miles per hour in kilometers per hour?
- 100 miles per hour equals 160.9344 kilometers per hour.
- What is 1 kilometer per hour in miles per hour?
- 1 kilometer per hour equals 0.62137119 miles per hour.
- Is this mile per hour to kilometer per hour converter free?
- Yes. The converter is free, needs no sign-up, and runs entirely in your browser — the values you enter never leave your device.