3 min read · May 18, 2027
Miles to Kilometers for Runners: 5K, 10K, and Marathon Distances
A marathon is 26.2 miles, which converts to exactly 42.195 km (the official distance is defined in kilometers, and 26.2 miles is the commonly rounded English equivalent). A 5K is 3.11 miles, and a 10K is 6.21 miles.
Common race distances, both units
5K = 3.107 miles. 10K = 6.214 miles. Half marathon = 13.1 miles = 21.1 km. Full marathon = 26.2 miles = 42.195 km. Race distances are almost always defined in kilometers first internationally (hence the 'K' naming), with the mile figure being the commonly used rounded conversion in countries that measure distance in miles.
The marathon's oddly specific 26.2-mile / 42.195 km distance comes from a fixed historical course length standardized in 1921 — it isn't a round number in either unit, which is exactly why runners memorize it rather than deriving it.
Converting your pace, not just the distance
Pace in minutes per mile converts to minutes per kilometer by dividing by 1.60934 (the number of km in a mile) — an 8:00/mile pace is roughly 8:00 ÷ 1.60934 ≈ 4:58/km. Going the other way, multiply a min/km pace by 1.60934 to get min/mile.
This matters directly for race strategy: a runner training with a US watch set to miles who signs up for a European race measured in kilometers needs to convert their target pace before race day, not do the math on the fly at mile 20.
Quick mental-math shortcut
For a fast estimate without an exact calculation, multiply miles by 1.6 to get a close kilometer figure, or multiply kilometers by 0.62 to get a close miles figure — accurate enough for training-log purposes, though race-day distances and official times should use the exact conversion factor.
Put it into practice
The fastest way to learn the math is to play with the numbers.
Open the Unit Converter