Unit Conversions
Kilometers vs Miles: A Complete Conversion Guide
Understand the difference between kilometers and miles, learn the conversion factor, and master quick estimation techniques for everyday use.
Kilometers and miles are both units of distance, but they're used in different parts of the world. The United States, United Kingdom (for road distances), and a handful of other countries use miles. Almost everywhere else uses kilometers.
The Conversion Factor
1 mile = 1.60934 kilometers. Or going the other way: 1 kilometer = 0.621371 miles. The relationship is fixed — no rounding or approximation is built into the conversion.
Common Reference Points
- 1 km ≈ 0.62 miles
- 5 km ≈ 3.1 miles (a popular race distance)
- 10 km ≈ 6.2 miles
- Half marathon: 21.1 km = 13.1 miles
- Marathon: 42.2 km = 26.2 miles
- 100 km ≈ 62 miles
Quick Mental Conversion
To convert km to miles in your head, multiply by 0.6 (or divide by 1.6). For miles to km, multiply by 1.6. These shortcuts are within 3% of the precise answer — plenty accurate for driving or running.
Speed: KPH vs MPH
The same factor applies to speed. 100 km/h = 62 mph. The typical UK motorway speed limit of 70 mph equals 113 km/h. Many GPS units let you toggle between the two, which is useful when driving across country borders.