How to convert miles to kilometers
One statute mile equals exactly 1.609344 kilometers — a value fixed by international agreement in 1959, so it never changes. That gives you two simple rules:
- Miles to km: multiply by 1.609344 →
km = miles × 1.609344 - Km to miles: divide by 1.609344, or multiply by 0.621371 →
miles = km × 0.621371
Using the converter above:
- Type the number of miles in the first field (decimals are fine).
- Read the kilometers instantly, plus the distance in meters and the same conversion expressed as a speed (mph to km/h).
- Got kilometers instead? Type in the second field — it works in both directions.
For quick mental math, remember that 5 miles is almost exactly 8 km, so multiply miles by 8 and divide by 5. The shortcut lands within 0.6 % of the true value.
Worked example
You are planning a road trip and the map says the next city is 250 miles away, but the rental car’s odometer reads in kilometers. 250 × 1.609344 = 402.34 km. Going the other way: a road sign abroad says 100 km to your exit, and 100 ÷ 1.609344 = 62.14 miles — about an hour of driving at highway speed.
Miles to kilometers table
| Miles | Kilometers | Reference |
|---|---|---|
| 1 | 1.61 | — |
| 3.1 | 4.99 | ≈ a 5K race |
| 5 | 8.05 | — |
| 6.2 | 9.98 | ≈ a 10K race |
| 10 | 16.09 | — |
| 13.1 | 21.08 | half marathon |
| 26.2 | 42.16 | marathon |
| 50 | 80.47 | 50-mile ultra |
| 100 | 160.93 | 100-mile ultra |
Runner’s note: the official distances are 21.0975 km for the half marathon (13.11 miles) and 42.195 km for the marathon (26.22 miles) — “13.1” and “26.2” are the popular rounded versions you see on bumper stickers.
Race distances: 5K, 10K and beyond
Most of the world measures road races in kilometers, which is why American runners constantly convert. A 5K is 3.11 miles, a 10K is 6.21 miles, and if your treadmill shows miles while your training plan is metric, a 10-minute-mile pace works out to roughly 6 minutes 13 seconds per kilometer. Strava, Garmin and most running apps let you switch units, but knowing the conversions helps you sanity-check any workout.
Speed limits: mph vs km/h
Because mph means miles per hour, speeds convert with the same 1.609344 factor. If you drive outside the US, the km/h signs translate like this: 80 km/h = 49.71 mph, 100 km/h = 62.14 mph and 120 km/h = 74.56 mph. In the opposite direction, a US interstate limit of 70 mph equals 112.65 km/h. The United States is one of the very few countries that still posts road signs in miles; almost everywhere else uses kilometers.
Frequently asked questions
How many kilometers are in a mile?
Exactly 1.609344 kilometers, or 1,609.344 meters. For rough estimates use 1.6; for anything that matters, use the full factor or the converter above.
What is the difference between a statute mile and a nautical mile?
The statute (land) mile is 1.609344 km. The nautical mile, used in aviation and sailing, is defined as exactly 1.852 km — about 15 % longer, or 1.15 statute miles. Road distances, running races and this converter all use the statute mile.
How do I convert mph to km/h?
Multiply by the same factor: km/h = mph × 1.609344. For example, 65 mph = 104.61 km/h. The converter shows this automatically in the “As a speed” card, since distance and speed share the identical ratio.
Why does the US still use miles?
The mile came with the British imperial system in colonial times, and metrication never finished: the Metric Conversion Act of 1975 made the switch voluntary, road-sign conversion plans were dropped, and everyday life stayed with miles, feet and pounds. Science, medicine and the military in the US do work in metric — the roads just never followed.