Convert miles per hour to kilometres per hour in one step. Type a value, change the units if you need a different pair, and the answer updates as you type, with the reverse rate and a quick reference list.
Results are estimates for planning. Check the figures before you make a financial or health decision.
How to convert miles per hour to kilometres per hour
Multiply the number of mph by 1.609344 to get km/h:
km/h = mph × 1.609344
To go the other way, divide by 1.609344 (or multiply by 0.621371). The converter stores each unit as a multiple of a base unit, so you can also pick any other pair of units from the same group.
Worked example
Using the default values in the converter above:
| Input | Value |
|---|---|
| Value | 70 |
| From | Miles per hour |
| To | Kilometres per hour |
70 miles per hour equals 112.65408 kilometres per hour
MPH to KM/H reference table
| Miles per hour | Kilometres per hour |
|---|---|
| 5 mph | 8.04672 km/h |
| 10 mph | 16.09344 km/h |
| 20 mph | 32.18688 km/h |
| 30 mph | 48.28032 km/h |
| 40 mph | 64.37376 km/h |
| 50 mph | 80.4672 km/h |
| 60 mph | 96.56064 km/h |
| 70 mph | 112.65408 km/h |
| 100 mph | 160.9344 km/h |
Tips and common mistakes
UK road signs and speed limits use miles per hour, while most of Europe uses kilometres per hour. A mile is 1.609344 km, so 70 mph is about 112.7 km/h and 100 km/h is about 62.1 mph.
A knot is one nautical mile per hour, and a nautical mile is exactly 1,852 metres, so 1 knot is 1.852 km/h or about 1.151 mph. Knots are used at sea and in aviation, including wind speeds on marine forecasts.
The usual mistake is using the 1.6 shortcut and then forgetting which way it goes: multiply by about 1.6 to go from mph to km/h, and divide by about 1.6 (or multiply by 0.62) to go back.
Frequently asked questions
How many kilometres per hour are in 1 mph?
1 mph equals 1.609344 kilometres per hour.
How do I convert mph to km/h by hand?
Multiply the mph figure by 1.609344. For example, 70 mph × 1.609344 = 112.65408 km/h.
How do I convert km/h back to mph?
Divide the km/h figure by 1.609344, or multiply it by 0.621371. For example, 112.65408 km/h is 70 mph.
Is this conversion exact?
Yes. The mile, nautical mile and knot are defined exactly in metric terms, so the factor is exact apart from rounding.