Kilometers to Miles Converter
1 kilometer = 0.621371 miles
The conversion from kilometers to miles bridges two measurement traditions in distance and dimension measurement. The mile descends from the Roman "mille passus" (a thousand paces), each pace being two steps. Knowing that 1 km equals 0.621371 mi is useful for road distances in the US and UK, aviation, and running events.
Did you know? Did you know? A marathon is 42.195 km. Converting that to miles: that is approximately 26.2188 miles.
Conversion Formula
miles = kilometers x 0.621371
To convert kilometers to miles, multiply the distance in kilometers by 0.621371. This factor comes from the definition of 1 mile as exactly 1,609.344 meters. Since 1 km = 1,000 meters, dividing 1,000 by 1,609.344 gives the conversion factor.
Kilometers to Miles Table
| Kilometers (km) | Miles (mi) |
|---|---|
| 1 | 0.621371 |
| 5 | 3.10686 |
| 10 | 6.21371 |
| 15 | 9.32057 |
| 20 | 12.4274 |
| 50 | 31.0686 |
| 100 | 62.1371 |
| 200 | 124.274 |
| 500 | 310.686 |
| 1000 | 621.371 |
About Kilometers to Miles
The kilometer-to-mile conversion is one of the most commonly used distance conversions in the world. Understanding this conversion is essential for international travel, running events, and vehicle odometer readings.
For reference, the distance from Paris to London is approximately 343 km, which equals about 213 miles. A full marathon is 42.195 km - that's 26.219 miles. The flight distance from New York to Los Angeles is roughly 3,944 km or 2,451 miles.
Most countries use kilometers as their standard unit of distance, while the United States, United Kingdom (for road signs), and a few other nations still rely on miles. If you're driving in continental Europe and see a sign reading 120 km, that's about 74.6 miles - right around the typical highway speed limit in the US.
Runners often need this conversion too. A 5K race is 3.107 miles, a 10K is 6.214 miles, and a half marathon at 21.1 km equals 13.1 miles. Many GPS watches let you toggle between km and miles, but knowing the rough conversion helps when training plans use different units.
A useful mental shortcut: multiply kilometers by 0.6 for a quick approximation. So 100 km is roughly 60 miles, and 50 km is about 30 miles. For more precision, multiply by 0.621371.
Frequently Asked Questions
How many miles is 100 km?
100 kilometers equals 62.1371 miles. This is roughly the distance from San Francisco to Sacramento, California.
What is the quick way to convert km to miles in your head?
Multiply by 0.6 for a fast estimate, or use the Fibonacci sequence trick: consecutive Fibonacci numbers approximate the km-to-mile ratio (e.g., 8 km is about 5 miles, 13 km is about 8 miles).
Why do some countries use km and others use miles?
Most countries adopted the metric system after the French Revolution introduced it in 1799. The US, Liberia, and Myanmar still primarily use miles for road distances, largely due to historical convention and the cost of switching infrastructure.
Is a km longer than a mile?
No, a mile is longer than a kilometer. 1 mile equals 1.60934 km, so a mile is about 61% longer than a kilometer.