Loading page
Fuel efficiency from distance and fuel.
The Mileage Calculator works out how far your vehicle travels per unit of fuel — its fuel economy. Enter the distance covered and the fuel consumed, and it returns the efficiency in your chosen units along with the common alternatives so you can compare figures from any source.
It supports both metric (kilometres and litres) and US customary (miles and gallons) inputs, and always shows km/L, miles per gallon (mpg) and litres per 100 km side by side. This is the quickest way to check a tank-to-tank reading or verify a manufacturer's claimed economy.
US gallons are used for mpg. One Imperial (UK) gallon is larger (4.546 L), so UK mpg figures are about 20% higher for the same real economy.
km/L and mpg measure distance per unit of fuel (higher is better). L/100km measures fuel per fixed distance (lower is better). All three describe the same efficiency, just expressed differently.
This calculator uses the US gallon (3.785 L). The UK Imperial gallon is 4.546 L, so an Imperial mpg figure is roughly 1.2 times the US mpg for the same actual fuel economy.
Divide km/L by 0.425144 (or multiply by about 2.352) to get US mpg. To go the other way, multiply mpg by 0.425144 to get km/L.
Use a full tank or at least 200–300 km for a reliable figure. Short trips and cold starts distort economy, so a full tank averaged over mixed driving is best.