KM to miles converter, kilometers to miles.

To convert km to miles, multiply the kilometers by 0.621371. So 1 km is 0.62137 miles, 10 km is 6.21371 miles and 100 km is 62.13712 miles. The same number works for speed: 100 km/h is 62.14 mph. This converter also goes the other way and shows the distance in meters, feet and nautical miles.

How to use the converter

1. Type a distance in the Kilometers (km) box, for example 42 for a road sign. The big result shows miles.
2. Type miles in the Miles (mi) box to go the other way. A sign reading 50 miles is 80.4672 km.
3. Pick Decimals. 1 or 2 is enough for a road, more for a map distance.
4. Look at the cards for meters, feet and nautical miles.
5. Use Copy result or Copy link, click a row in Common values to load it, or press Print chart for a sheet to keep in the car.

The definition: 1.609344 kilometers

The international mile is exactly 5,280 feet, and the foot is exactly 0.3048 meter, so the mile is exactly 1,609.344 meters or 1.609344 km. NIST Handbook 44 (2026), Appendix C states "1 mile (mi) 5 280 feet (exactly) 1.609 344 kilometers (exactly)" and "1 kilometer (km) 1 000 meters (exactly)". NIST Special Publication 811, Appendix B.8 lists the mile to kilometer factor as 1.609 344 and marks it exact. Both were checked 18 Oct 2026. Kilometers to miles is the reverse division: miles = kilometers ÷ 1.609344. It never ends, so each answer is rounded in the last digit only.

A mental shortcut and how good it is

Multiply by 5 and divide by 8. That is the same as multiplying by 0.625. For 80 km: 80 × 5 = 400, 400 ÷ 8 = 50 miles. The exact answer is 49.7097 miles. The shortcut is 0.58 percent high. The popular 0.6 is worse: it is 3.44 percent low. A better small step is 0.62, which is 0.22 percent low. For 80 km the 5/8 trick says 50 miles against the exact 49.71, which is 0.29 miles high and fine for a drive.

Worked examples

• A road sign: next town 120 km. 120 × 0.621371 = 74.56454 miles.
• A 5K run. 5 × 0.621371 = 3.10686 miles. A 10K is 6.21371 miles.
• A speed limit of 100 km/h. 100 × 0.621371 = 62.14 mph. A limit of 130 km/h is 80.78 mph.
• A 300 km drive. 300 × 0.621371 = 186.41 miles.
• A US sign: 50 miles to go. 50 × 1.609344 = 80.47 km.

Mistakes that are specific to km and miles

Fuel use is the trap. The same 0.62 does not turn liters per 100 km into miles per gallon: that is an inverse, not a multiplication. Use a fuel economy tool for it. The second trap is the sea mile. A nautical mile is exactly 1,852 meters, so 1 nautical mile is 1.1508 statute miles, not 1. The third is the survey mile: the US survey mile differs from the international mile by two parts in a million. NIST Handbook 44 (2026), Appendix C notes that the survey foot is being replaced by the international foot, and the converter uses the international mile.

Race distances and speed limits

The same factor changes a distance and a speed. The table gives some common distances in kilometers with their exact value in miles, and some common speed limits in km/h with the same value in mph.

The table is only a lookup of the factor, so the distances and limits are examples, not official race lengths or road rules.

Doing a trip in your head

For a day's driving, round up. A 400 km drive is 248.5 miles, so call it 250 and you are 1.5 miles out. A 100 km/h limit is 62.1 mph, so 62 is close. For a run, a pace in minutes per kilometer is not simply the pace per mile: 5 minutes per km is 5 × 1.609344 = 8.05 minutes per mile, or 8 minutes 3 seconds. Multiply the time, not the distance, in that case.

Who uses km to miles

Drivers renting a car abroad. Runners comparing a 10K with a 6 mile route. Cyclists reading a metric route. Travellers reading a road sign or a train timetable. Pilots and sailors use nautical miles, shown on a card. For short lengths see the CM to inches converter. The same idea for weights is in the KG to LBS converter, and for temperatures in the Fahrenheit to Celsius converter.