km to Miles Calculator - Convert Kilometers to Miles

About the km to Miles Calculator

Kilometres measure road distances, running races, hiking trails and flight ranges in most of the world, but miles are still used on roads in the United States and the United Kingdom, and many runners and drivers think in miles wherever they are. A race entry for a 10K, a road sign in France or a car's range quoted in kilometres all make more sense once they are converted.

This km to miles calculator converts kilometres to miles exactly. It also gives the distance in yards, or feet for short distances, in nautical miles, and shows roughly how long it takes to walk at 5 km/h and to drive at 100 km/h.

How to Use the km to Miles Calculator

Enter the distance in kilometres. Decimals are fine, such as 21.0975 for a half marathon.

The miles appear at once with the other units and the travel times.

The Formula

  miles  = kilometres ÷ 1.609344
  yards  = miles × 1,760
  nautical miles = kilometres ÷ 1.852

The factor 1.609344 is exact: the mile has been defined as exactly 1,609.344 metres since 1959. Dividing by it is the same as multiplying by about 0.621371.

Step-by-Step Example

A 5 km race.

  5 ÷ 1.609344 = 3.10686 mi

A 5K is 3.10686 miles, just over three miles. Walking at 5 km/h it takes about an hour; driving at 100 km/h, about 3 minutes.

A marathon, 42.195 km.

  42.195 ÷ 1.609344 = 26.2188 mi

That is the familiar 26.2 miles.

Race Distances

  5 km            3.10686 mi
  10 km           6.21371 mi
  15 km           9.32057 mi
  half marathon   21.0975 km = 13.1094 mi
  marathon        42.195 km  = 26.2188 mi
  50 km           31.0686 mi
  100 km          62.1371 mi

Runners training in miles for a race in kilometres, or the other way round, can use these to set target splits. A 5K run at 8 minutes per mile finishes in about 24 minutes 51 seconds, and a 10K at the same pace in about 49 minutes 43 seconds, which is why many runners set their goals just under those round numbers.

Driving and Road Signs

Road signs in most countries show kilometres, and car hire abroad often means a speedometer and trip computer in km. A sign reading "Paris 120" means about 74.6 miles; at a steady 100 km/h, about 62 mph, that is 1 hour 12 minutes of driving. Fuel ranges, too, are often quoted in kilometres: a range of 600 km is about 373 miles.

Quick Mental Conversions

Two easy shortcuts work well:

Multiply by 0.6 for a quick, slightly low answer: 80 km is about 48 miles (exactly 49.7).

Multiply by 5 and divide by 8 for a closer one: 80 × 5 ÷ 8 = 50 miles.

The 5/8 rule is less than 1 percent out, because 5/8 is 0.625 against the exact 0.62137. It also explains why 8 km is almost exactly 5 miles.

Nautical Miles

At sea and in the air, distances are given in nautical miles of 1,852 metres, about 15 percent longer than a statute mile. A 100 km flight leg is about 54 nautical miles. Nautical miles are tied to latitude — one nautical mile is roughly one minute of arc along a meridian — which makes them convenient for navigation with charts.

Pace Per Kilometre and Per Mile

Runners who switch between the two units need to convert pace as well as distance. A pace per kilometre is multiplied by 1.609344 to get the pace per mile, so 5 minutes per kilometre is about 8 minutes 3 seconds per mile, and 6 minutes per kilometre is about 9 minutes 39 seconds per mile. Going the other way, divide the pace per mile by 1.609344: 10 minutes per mile is about 6 minutes 13 seconds per kilometre. Many GPS watches let you choose either unit, but training plans and race results often mix them, so it helps to know both figures for your usual pace.

Why Both Units Survive

The kilometre became the standard road unit across Europe during the nineteenth and twentieth centuries as countries adopted the metric system. The United Kingdom kept miles for road signs and speed limits even after metrication of most other measures, and the United States never switched. Aviation and shipping settled on the nautical mile. Sport went its own way: athletics tracks and most road races are measured in metres and kilometres, even in America, while some classic races and horse racing still use miles and furlongs.

Understanding Your Result

The headline is the distance in miles.

The yards and feet line gives yards, and feet as well for distances under a mile.

The nautical miles line gives the distance for sea and air navigation.

The travel time line shows how long the distance takes walking at 5 km/h and driving at 100 km/h.

When Should You Use This Calculator?

Use it for running and cycling race distances in kilometres.

Use it for road signs, car hire and fuel ranges abroad.

Use it for hiking routes and trail guides in kilometres.

Use it to compare distances in news, maps and travel guides.

Common Mistakes

Multiplying by 1.609344. From kilometres to miles, divide.

Using 0.6 for precise work. It is about 3.4 percent low; use the exact factor.

Confusing miles and nautical miles. Nautical miles are about 15 percent longer.

Treating decimal miles as miles and yards. 3.1 miles is 3 miles 176 yards.

Forgetting that race distances are exact in kilometres. A 10K is 6.21371 miles, not 6.2 exactly.