Km/h to mph
One km/h equals 0.6213711922 mph. Type any number and the answer appears as you type — the maths happens in your browser.
The same value in every unit
| Unit | Value |
|---|
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Common values
| km/h | mph |
|---|---|
| 1 km/h | 0.62137119 mph |
| 2 km/h | 1.2427424 mph |
| 3 km/h | 1.8641136 mph |
| 5 km/h | 3.106856 mph |
| 10 km/h | 6.2137119 mph |
| 15 km/h | 9.3205679 mph |
| 20 km/h | 12.427424 mph |
| 25 km/h | 15.53428 mph |
| 50 km/h | 31.06856 mph |
| 100 km/h | 62.137119 mph |
| 500 km/h | 310.6856 mph |
| 1000 km/h | 621.37119 mph |
How to use
- Enter the number of km/h in the field.
- The result in mph updates on every keystroke.
- Use the table below for the values people look up most often.
Formula and reverse conversion
The formula
To convert by hand: mph = km/h ÷ 1.609344. Going back the other way, one mph is 1.609344 km/h.
Where the odd number comes from
The factor is not a round number because the imperial units are defined through the metric ones by international agreement: an inch is exactly 25.4 mm and a pound is exactly 0.45359237 kg. Everything else follows from those definitions.
mph = km/h ÷ 1.609344
Frequently asked questions
How many mph are in one km/h?
One km/h is 0.6213711922 mph.
How do I convert km/h to mph?
Multiply by the factor: mph = km/h ÷ 1.609344.
Is the result exact?
The factors are the exact legal definitions, and up to ten significant digits are kept in the answer. Rounding happens only in the display.
How do I convert mph back to km/h?
One mph is 1.609344 km/h — or open the reverse page linked below.