How this calculator works
The international mile is defined as exactly 1,609.344 m, which is 1.609344 km. A kilometre is 1,000 m, so one kilometre is 1 / 1.609344 miles, about 0.621371. Road distances in Canada are usually posted in kilometres, while the United States and the United Kingdom use miles. The nautical mile is different again at exactly 1,852 m and is used for sea and air navigation.
Formula
mi = km / 1.609344. km = mi x 1.609344. A nautical mile is 1.852 km exactly and is not the same as a statute mile.
Worked example
5 km = 3.10686 mi. 10 km = 6.21371 mi. A marathon of 42.195 km is 26.2188 mi. 100 km = 62.1371 mi. 1 mi = 1.60934 km.
Advertisement
Frequently asked questions
Why is 5 km not exactly 3 miles?
Five kilometres is about 3.10686 miles. The two distances happen to be close because 1.6 is a rough conversion, but the exact mile is 1.609344 km, so 5 km is slightly more than 3 miles.
How long is a 10 km race in miles?
10 km is 6.21371 miles. A 5 km race is 3.10686 miles, often rounded to 3.1 miles, and a half marathon of 21.0975 km is 13.1094 miles.
Is a nautical mile the same as a mile?
No. A nautical mile is exactly 1,852 m, about 1.15078 statute miles. It matches one minute of latitude and is used in navigation.
Which is longer, a mile or a kilometre?
A mile is longer. One mile is 1.609344 km, so a distance in miles becomes a larger number of kilometres, and a distance in kilometres becomes a smaller number of miles.