Mile to km Converter
＋More features: table of five units, speed conversion
Table of km, miles, nautical miles, yards and feet
Puts one distance into five units at once, including the yards used in golf and the feet used for altitude.
Speed conversion (mph, km/h, knots)
Turns a US speed limit such as “65 mph”, or the knots used by ships and aircraft, into km per hour.
Type a number and see straight away how many km a mile is (and how many miles a km is). Nautical miles, used at sea and in the air, are covered too. Japan signs its roads in kilometers, so this is handy for reading US road signs, marathon distances, airline mileage or the odometer of an imported used car.
How to use
- Enter the distance.
- Choose the unit the number is in (miles, km or nautical miles).
- All three units appear as soon as you type — no button needed.
How it is calculated
- 1 mile (international mile) = 1.609344 km (an exact defined value)
- 1 nautical mile = 1.852 km (an exact defined value; it comes from the length of one minute of latitude and is used at sea and in aviation)
- Worked example: the 26.2 miles of a marathon is about 42.16 km (the exact race distance is 42.195 km = 26.219 miles).
- A “knot” of speed is one nautical mile per hour (20 knots is about 37 km/h).
Sources and assumptions
- Arithmetic based on the defined values of the international mile and the international nautical mile (see the National Metrology Institute of Japan, AIST, in Japanese).
Assumptions and notes
- US speed limit signs are in miles per hour (mph). 60 mph is about 97 km/h, so the number looks smaller than you may expect while the speed is high.
- The “miles” of an airline mileage program come from distance, but the number actually awarded depends on the fare type.
Frequently asked questions
Why is a marathon 42.195 km?
It comes from the 26 miles 385 yards adopted at the 1908 London Olympics. That is 26.219 miles = 42.195 km.
A US road with a 60-mile limit is how many km per hour?
About 97 km/h (60 × 1.609344 = 96.56 km). When you drive a rental car, get into the habit of multiplying the number on the sign by 1.6 to read it in km.
Why is a nautical mile 1.852 km?
It comes from the distance of one minute of latitude (1/60 of a degree) on the Earth. Because charts are drawn in latitude and longitude, ships and aircraft still use nautical miles.