UK MPG calculator
Calculate UK miles per gallon from miles driven and litres used, then convert to litres per 100km.
Formula: UK MPG = (Miles Driven × 4.54609) ÷ Litres Used, and L/100km = 282.481 ÷ UK MPG.
Use your real MPG with FuelRoute’s route planner so detour recommendations reflect how thirsty your car is.
Frequently asked questions
How do I work out miles per gallon (MPG) from litres in the UK?
Multiply the miles driven by 4.54609 and divide by the litres of fuel used: UK MPG = (Miles × 4.54609) ÷ Litres. For example, driving 400 miles on 40 litres of fuel equals 10 miles per litre, which is 45.5 MPG in UK imperial gallons.
What is 10 miles per litre in UK MPG?
10 miles per litre equals 45.46 MPG in the UK (because 1 imperial gallon is 4.54609 litres, so 10 × 4.54609 = 45.46 MPG). In US gallons (3.785 litres), 10 miles per litre is 37.85 US MPG.
What is the average miles per litre and MPG in the UK?
Most modern UK petrol cars achieve 8.5 to 11 miles per litre (39 to 50 UK MPG), while UK diesel cars typically achieve 10.5 to 13 miles per litre (48 to 59 UK MPG) depending on urban versus motorway driving.
Is this UK MPG or US MPG?
FuelRoute uses imperial (UK) gallons. One UK gallon is 4.54609 litres (about 20% larger than the 3.785-litre US gallon), matching official UK vehicle figures.
How do I convert UK MPG to litres per 100km (L/100km)?
Divide 282.481 by your UK MPG figure: L/100km = 282.481 ÷ UK MPG. For example, 45 MPG equals 6.28 L/100km.
Why does MPG matter for fuel stops?
Detour cost depends on how thirsty your car is. FuelRoute’s route planner uses your MPG so a cheaper station is only recommended when the pump saving beats the extra miles.