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MPG & fuel economy
Calculate UK MPG from a fill-up and convert it to US MPG and L/100 km.
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For a useful measurement, compare similar full-tank levels and record all distance and fuel between them.
How it works
UK MPG = miles × 4.54609 ÷ litres. US MPG = miles × 3.785411784 ÷ litres. L/100 km = litres ÷ (miles × 1.609344) × 100.
A quick example
300 miles on 35 litres is about 38.97 UK MPG, 32.45 US MPG or 7.25 L/100 km.
Good to know
Why are UK and US MPG different?
The mile is the same but the gallons differ in volume. Always check which gallon a vehicle specification uses.
Is higher always better?
Higher MPG means less fuel used over the same distance. For L/100 km, lower is better.