Convert kilometres per hour to miles 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 kilometres per hour to miles per hour
Multiply the number of km/h by 0.621371 to get mph:
mph = km/h × 0.621371
To go the other way, divide by 0.621371 (or multiply by 1.609344). 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 | 100 |
| From | Kilometres per hour |
| To | Miles per hour |
100 kilometres per hour equals 62.137119 miles per hour
KM/H to MPH reference table
| Kilometres per hour | Miles per hour |
|---|---|
| 5 km/h | 3.106856 mph |
| 10 km/h | 6.213712 mph |
| 20 km/h | 12.427424 mph |
| 30 km/h | 18.641136 mph |
| 40 km/h | 24.854848 mph |
| 50 km/h | 31.06856 mph |
| 60 km/h | 37.282272 mph |
| 70 km/h | 43.495983 mph |
| 100 km/h | 62.137119 mph |
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 miles per hour are in 1 km/h?
1 km/h equals 0.621371 miles per hour.
How do I convert km/h to mph by hand?
Multiply the km/h figure by 0.621371. For example, 100 km/h × 0.621371 = 62.137119 mph.
How do I convert mph back to km/h?
Divide the mph figure by 0.621371, or multiply it by 1.609344. For example, 62.137119 mph is 100 km/h.
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.