United Kingdom

MPG Calculator UK

The MPG calculator UK works in Imperial (UK) gallons, which are larger than US gallons — so the same car always shows a higher MPG figure in the UK. Enter your miles and the fuel used in either litres or UK gallons, and this miles per gallon calculator UK tool returns your true Imperial MPG.

Because UK drivers buy fuel in litres but think in miles, this also doubles as a miles per gallon converter UK: it shows your L/100km equivalent and the US MPG figure (which is always lower than the UK number) so you can compare against American specs. One UK gallon equals 4.54609 litres, or about 1.20095 US gallons.

Add a fuel price and it becomes a miles per gallon cost calculator UK, returning pence per mile and total fuel cost in pounds. When you enter litres, the price field asks for pence per litre; when you enter UK gallons, it asks for pounds per UK gallon. For more conversions see our Miles Per Litre and L/100km tools.

Miles Driven

Fuel Unit

Fuel Used (litres)

Fuel Price (p/litre) — optional

How to Use

Enter the miles driven.
Choose your fuel unit — litres or UK gallons.
Enter the fuel used in that unit.
Optionally add the fuel price for cost results.
Click Calculate UK MPG (or press Enter).

Got Questions?

MPG Calculator UK FAQ

What is the difference between UK and US MPG? +

UK MPG uses Imperial gallons (4.546 litres), US MPG uses US gallons (3.785 litres). The same car gets about 20% higher MPG in the UK figure. For example, 40 UK MPG = 33.3 US MPG.

How do I calculate MPG in the UK from litres? +

Divide miles driven by litres used, then multiply by 4.54609. Formula: MPG = (miles ÷ litres) × 4.546.

What is good MPG for a UK car? +

In UK figures, 50+ MPG is excellent, 40–50 MPG is good, 30–40 MPG is average. Most modern petrol cars achieve 35–50 UK MPG. Diesels typically score higher.

How do I convert UK MPG to litres per 100km? +

Use the formula: L/100km = 282.481 ÷ UK MPG. For example, 50 UK MPG = 5.65 L/100km.

Is the WLTP MPG figure accurate? +

WLTP (Worldwide Harmonised Light Vehicle Test Procedure) is more realistic than the old NEDC test, but real-world MPG is typically 10–20% lower depending on driving style, road type, and conditions.