KM to Miles

How to convert kilometers to miles

One kilometer equals about 0.621371 miles, so multiply kilometers by 0.6214 (or roughly divide by 1.61) to get miles.

Example: a 5 km park run is about 3.1 miles, a half marathon (21.1 km) is 13.1 miles, and a full marathon (42.2 km) is 26.2 miles.

Kilometers to miles table

The Fibonacci trick for doing it in your head

Consecutive Fibonacci numbers (3, 5, 8, 13, 21, 34) sit at almost exactly the kilometer-to-mile ratio, because that ratio (0.6214) is close to the golden ratio's inverse (0.618). So the next number down the sequence converts the one above it.

That gives you 5 km ≈ 3 miles, 8 km ≈ 5 miles, 13 km ≈ 8 miles and 21 km ≈ 13 miles — each within about half a percent. For values in between, halve or double a known pair: 40 km is double 20 km, so about 25 miles.

Speed limits abroad

The same factor converts km/h to mph, which matters most when you are driving in a country that signs the other unit.

Converting running pace

Pace goes the opposite way to distance: a mile is longer than a kilometer, so your minutes-per-mile number is bigger. Multiply your min/km pace by 1.609 to get min/mile.

Race distances in both units

• 5 km = 3.11 miles — the standard parkrun distance.
• 10 km = 6.21 miles.
• Half marathon = 21.0975 km = 13.11 miles.
• Marathon = 42.195 km = 26.22 miles.
• The odd marathon distance is historical: it was fixed at 26 miles 385 yards at the 1908 London Olympics and standardised afterwards.

Fuel economy converts differently

Fuel figures cannot be converted with the distance factor, because the two systems are inverses of each other: liters per 100 km measures fuel for a fixed distance, while miles per gallon measures distance for a fixed amount of fuel. Doubling one halves the other.

The conversion is a division rather than a multiplication — divide 235.2 by the l/100 km figure for US mpg, or 282.5 for UK mpg, since a UK gallon is larger than a US one.

Who still uses miles

Miles remain standard for road distances and speed limits in the United States and the United Kingdom, and in a small number of other countries. Almost everywhere else signs kilometers, which is why the conversion comes up most often when driving, flying or reading a race description from abroad.

One exception worth knowing: nautical miles (1.852 km) are used in aviation and at sea and are a different unit entirely — do not convert them with the 0.6214 factor.