Convert miles per UK gallon to litres per 100 km in one step. Type a value, change the units if you need a different pair, and the answer updates as you type, with the reverse rate and a quick reference list.
Results are estimates for planning. Check the figures before you make a financial or health decision.
How to convert miles per UK gallon to litres per 100 km
Fuel economy is a ratio, and litres per 100 km is the inverse of distance per volume, so the conversion divides rather than multiplies. The converter first turns your figure into litres per 100 km, using 282.481 ÷ mpg (UK) or 235.215 ÷ mpg (US) or 100 ÷ km per litre, and then converts to the unit you chose.
l/100 km = 282.481 ÷ mpg (UK)
Worked example
Using the default values in the converter above:
| Input | Value |
|---|---|
| Value | 45 |
| From | Miles per UK gallon |
| To | Litres per 100 km |
45 miles per UK gallon equals 6.277354 litres per 100 km
MPG to Litres per 100 KM reference table
| Miles per UK gallon | Litres per 100 km |
|---|---|
| 20 mpg (UK) | 14.124047 l/100 km |
| 30 mpg (UK) | 9.416031 l/100 km |
| 40 mpg (UK) | 7.062023 l/100 km |
| 50 mpg (UK) | 5.649619 l/100 km |
| 60 mpg (UK) | 4.708016 l/100 km |
| 70 mpg (UK) | 4.035442 l/100 km |
| 80 mpg (UK) | 3.531012 l/100 km |
| 100 mpg (UK) | 2.824809 l/100 km |
Tips and common mistakes
Fuel economy can be measured two ways round. Miles per gallon and kilometres per litre go up as a car gets more efficient, while litres per 100 km goes down. That means the conversion is not a simple multiplication: 45 mpg (UK) is 6.28 l/100 km, and 30 mpg (UK) is 9.42 l/100 km.
UK and US gallons are different sizes, so 45 mpg (UK) is about 37.5 mpg (US). Check which one a car review or brochure uses, because American figures look lower for the same car.
UK petrol is sold in litres, but UK fuel economy is still quoted in mpg, so converting between the two is useful when working out running costs.
Frequently asked questions
How do I convert mpg (UK) to l/100 km?
Enter the figure in the converter above and choose the units. For example, 45 mpg (UK) is 6.277354 l/100 km. Because the scales run in opposite directions, the figures are inverses of each other.
Is a higher or lower figure better?
Higher miles per gallon or kilometres per litre is better, because the car travels further on the same fuel. For litres per 100 km, lower is better, because it uses less fuel to cover 100 km.
Are UK and US gallons the same?
No. A UK gallon is 4.54609 litres and a US gallon is about 3.785 litres, so the same car has a higher mpg figure in UK gallons than in US gallons.
What is a good fuel economy?
It depends on the type of vehicle, so compare like with like. Check the manufacturer's official figures and remember that real-world economy is usually lower than the test figure.