Why a fuel economy site has a distance converter
Every fuel economy figure has a distance inside it. Miles per gallon, litres per 100 kilometres, kilometres per litre: change the distance unit and the economy figure changes with it. If you measure your own consumption from a metric odometer and want to express it in mpg, you convert the kilometres to miles first, then divide by the gallons. The manual calculation guide walks through that, and this page does the distance step.
It is also simply a conversion people need on its own: a runner training in kilometres for a race advertised in miles, a driver renting a car abroad, someone reading a European road trip itinerary. The maths is the same in every case.
The formula
miles = kilometres ÷ 1.609344
The mile has been defined as exactly 1,609.344 metres since the international yard and pound agreement of 1959, which fixed the inch at 25.4 mm and therefore the mile at 63,360 inches. So the factor is not a measurement with error bars; it is a definition, and dividing by it gives an exact answer to as many decimals as you like. A quick mental version is to multiply by 0.6 and add a little: 10 km is about 6.2 miles.
Worked examples: race distances and road trips
A marathon is 42.195 km. Divide by 1.609344 and you get 26.219 miles, the familiar 26.2. A half marathon is 21.0975 km, or 13.109 miles. A 10K is 6.214 miles and a 5K is 3.107 miles, which is why 5K times and 3-mile times are close but not the same.
On the road, Paris to Lyon is about 465 km, which is 289 miles. A full tank that takes a car 700 km will take it 435 miles. Notice that in each case the miles figure is smaller: a mile is the longer unit, so any distance contains fewer of them.
Where each unit is used
The mile survives for road distances in the United States, the United Kingdom, Liberia and Myanmar, and on road signs in a few British overseas territories. Everywhere else the kilometre is standard, including in Ireland, Canada and Australia, all of which switched in the 1970s. The nautical mile, used at sea and in the air, is a different unit of 1,852 metres and is not what this page converts.
Litres and liters do not come into a distance conversion, but if you arrived here from a fuel economy question, the MPG to L/100km page combines the distance and the volume in one step.
Common errors
- Multiplying by 1.609 instead of dividing. Kilometres to miles makes the number smaller.
- Using 1.6 as the factor for long distances. On a 1,000 km trip that is a 6 mile error.
- Confusing the statute mile with the nautical mile when reading aviation or shipping distances.
- Reading km/h as mph on a rental car. 100 km/h is 62 mph; the conversion for speed is the same as for distance.