Miles to Kilometers Converter
Convert miles to kilometers by multiplying by exactly 1.609344. Includes a running and driving distance table, speed-limit conversions, and a mental-maths shortcut.
Miles to kilometers
Formula
Multiply by exactly 1.609344.
The factor is exact because the mile is 1,760 yards and the yard has been defined as exactly 0.9144 m since 1959. Multiply those out and you get 1,609.344 m to the mile, with nothing rounded away.
Worked example
Convert a 26.2 mile marathon:
And a 70 mph speed limit:
Speeds convert with the same factor as distances, because the hours on both sides cancel.
Conversion table
| Miles (mi) | Kilometers (km) |
|---|---|
| 1 | 1.609344 |
| 2 | 3.218688 |
| 3 | 4.828032 |
| 5 | 8.04672 |
| 10 | 16.09344 |
| 13.1 | 21.08241 |
| 20 | 32.18688 |
| 26.2 | 42.16481 |
| 50 | 80.4672 |
| 100 | 160.9344 |
| 250 | 402.336 |
| 500 | 804.672 |
Do it in your head
Multiply by 1.6, or — more accurately and just as easy — use the Fibonacci trick. Consecutive Fibonacci numbers approximate the ratio: 5 mi ≈ 8 km, 8 mi ≈ 13 km, 13 mi ≈ 21 km, 21 mi ≈ 34 km. Each is within 1% of the true value.
For anything else, add half the number and then a tenth: 40 mi → 40 + 20 + 4 = 64 km, against a true 64.4 km.
Running distances
Race distances are set in whichever system the event grew up in, which is why the conversions are untidy in one direction and exact in the other:
- 5 km = 3.107 mi
- 10 km = 6.214 mi
- Half marathon, 13.1 mi = 21.1 km
- Marathon, 26.2 mi = 42.2 km
- 1 mile = 1.609 km
- Ultramarathon 50 mi = 80.5 km
- 100 km = 62.14 mi
The marathon is officially 42.195 km, which rounds to 26.219 mi — the "26.2" is the rounding, not the definition.
Speed limits
- 20 mph = 32.2 km/h
- 30 mph = 48.3 km/h
- 50 mph = 80.5 km/h
- 60 mph = 96.6 km/h
- 70 mph = 112.7 km/h — the UK motorway limit
- 80 mph = 128.7 km/h
Note how 100 km/h (62.1 mph) sits between the US 55–65 mph limits, and 130 km/h (80.8 mph) matches the French autoroute limit.
FAQ
How many km is 1 mile? Exactly 1.609344 km.
How many miles is 1 km? 0.6213712 mi, just under five eighths.
Is a nautical mile the same? No. A nautical mile is 1,852 m — about 15% longer than a statute mile — and is used at sea and in the air.
Which countries still use miles? The United States, the United Kingdom, Liberia and Myanmar for road signs; the UK uses miles on roads but metres and kilometres almost everywhere else.