Miles to Kilometers Converter

How many kilometers are in a mile?

One mile is exactly 1.609344 kilometers. The figure is exact because the mile is now defined from the yard: 1,760 yards at 0.9144 m each make 1,609.344 m, which is 1.609344 km.

kilometers = miles × 1.609344To go back, divide: miles = kilometers ÷ 1.609344 (about km × 0.621371).

How to convert miles to kilometers

1. Type the distance in miles into the first box.
2. Read the kilometers from the second box; the result is rounded to six decimals.
3. For a quick estimate, multiply by 1.6, or use the Fibonacci trick described below.

Example: a half marathon is about 13.1 miles, and 13.1 × 1.609344 = 21.082406 km. A full marathon of 26.2 miles comes to 42.164813 km. The official distance is 26 miles 385 yards, or 42.195 km, and the familiar 26.2 is a rounded version of it.

Miles to kilometers conversion table

Estimating in your head

Multiplying by 1.6 is accurate to within 0.6%. On a 100 mile trip that gives 160 km, against an exact 160.9344 km, so the error is under a kilometer.

Another trick uses the Fibonacci numbers 3, 5, 8, 13, 21, 34. The ratio of neighboring terms is close to 1.618, which is close to the 1.609 miles-to-kilometers factor, so when a distance in miles is a Fibonacci number, the next Fibonacci number is nearly its value in kilometers: 5 miles is about 8 km (exactly 8.05), 8 miles about 13 km (12.87), and 13 miles about 21 km (20.92).

Where miles are still used

Road distances are signed in miles in the United States and the United Kingdom, along with a handful of countries and territories that follow them. Most of the rest of the world uses kilometers; Canada, for instance, switched its road signs to kilometers in the late 1970s. That is why drivers and travelers cross a border and must change units, and why a rental car's odometer is worth a glance.

Miles per hour and kilometers per hour

The same factor converts speed. A road limit given in miles per hour becomes kilometers per hour when multiplied by 1.609344.

For speed units in both directions, the mph to km/h converter handles speed units directly. Where distances rather than speeds are concerned, see kilometers to miles, miles to meters, miles to feet and miles to yards.