MPH to KM/H formula
1 mile per hour = 1.609344 kilometres per hour, and 1 kilometre per hour = 0.6213711922 miles per hour. 1,609.344 m in 3,600 s: exactly 0.44704 m/s. Speed limits in the US and UK.
MPH to KM/H chart
| Miles per hour (mph) | Kilometres per hour (km/h) |
|---|---|
| 5 | 8.0467 |
| 10 | 16.0934 |
| 15 | 24.1402 |
| 20 | 32.1869 |
| 25 | 40.2336 |
| 30 | 48.2803 |
| 35 | 56.327 |
| 40 | 64.3738 |
| 45 | 72.4205 |
| 50 | 80.4672 |
| 55 | 88.5139 |
| 60 | 96.5606 |
| 65 | 104.6074 |
| 70 | 112.6541 |
| 75 | 120.7008 |
| 80 | 128.7475 |
| 90 | 144.841 |
| 100 | 160.9344 |
| 120 | 193.1213 |
| 150 | 241.4016 |
| 200 | 321.8688 |
Values are rounded to 4 decimal places. The converter above shows more precision.
Worked examples
The UK motorway limit of 70 mph
70 mph × 1.609344 = 112.6541 km/h
70 miles per hour = 112.6541 kilometres per hour. About 112.7 km/h, a bit faster than the 110 km/h motorway limit in some European countries and slower than the 130 km/h in France.
A 30 mph town limit
30 mph × 1.609344 = 48.2803 km/h
30 miles per hour = 48.2803 kilometres per hour. About 48.3 km/h, close to the 50 km/h urban limit used across much of Europe.
Converting miles per hour to kilometres per hour in real life
The US and the UK post speed limits in miles per hour, while almost every other country uses kilometres per hour. Visitors driving a hire car, people comparing car specs (0 to 60 mph versus 0 to 100 km/h) and anyone reading weather reports with wind speeds in mph will need to convert.
A neat check: 50 mph is about 80 km/h and 70 mph, the UK motorway limit, is about 113 km/h. The two speeds are only equal at zero. For the conversion going the other way, use km/h to mph; for distances rather than speeds, use miles to km.