I'm moving from Germany to the UK and my car manual says 7.2 L/100km. What should I expect in mpg (Imperial)?

282.481 ÷ 7.2 = 39.2 mpg (Imperial). UK fuel cost calculators and insurance documents use Imperial mpg, so use this number when estimating running costs. At current UK fuel prices, 39 mpg (Imperial) is reasonable for a family car.

Why is the conversion factor 282.481 and not 235 like for US mpg?

The two factors reflect the two different gallon sizes. For US gallons (3.785 L): 3.785 × 100 ÷ 1.60934 = 235.214. For Imperial gallons (4.546 L): 4.546 × 100 ÷ 1.60934 = 282.481. The larger Imperial gallon means more distance per gallon, giving a higher mpg figure.

A UK car review says a model gets 55 mpg (Imperial). My equivalent European car is rated 5.1 L/100km. Are they the same?

Very close. 282.481 ÷ 5.1 = 55.4 mpg (Imperial). Yes, they are essentially the same vehicle — the small difference is rounding. Always check whether a UK mpg figure is Imperial before comparing to European L/100km. See also: [L/100km to mpg (US)](/fuel/l-per-100km-to-mpg/).

Is mpg (Imperial) used anywhere outside the UK?

Canada used Imperial mpg until metrication in the 1970s–80s, and some older Canadian sources still reference it. Ireland also used Imperial gallons historically. Today the UK is the primary market where Imperial mpg remains the standard for fuel economy labelling and car reviews.

L/100km to MPG (Imperial) Converter

Enter a value to instantly convert between fuel economy units.

From

Precision4 dp

1 Liters per 100km = 282.4809 MPG (Imperial)

Key Formulas

MPG (US) → Liters per 100km

L/100km = mpg × 235.215

Liters per 100km → MPG (US)

mpg = L/100km × 235.215

Km per Liter → MPG (US)

mpg = km/L × 2.35215

MPG (US) → Km per Liter

km/L = mpg × 0.425144

Formula

mpg (Imperial) = 282.481 ÷ L/100km

Comparing a European car's fuel economy to a UK or Canadian vehicle requires translating between two different systems that use different reference volumes. European manufacturers publish consumption in litres per 100 kilometres, while the UK and many Commonwealth countries use miles per Imperial gallon. The Imperial gallon (4.546 litres) is 20% larger than the US gallon, which is why mpg (Imperial) figures always look more impressive than mpg (US) for the same car. Getting this right matters: a 6 L/100km car achieves 47.1 mpg (Imperial) — not 39.2 mpg (US) — a meaningful difference when judging fuel costs or comparing against UK car reviews.

Source: NIST SP 811, Table B.8

Last reviewed: 2026-06-11 · see our methodology

Frequently Asked Questions

Real-World Examples

A frugal European diesel at 6 L/100km delivers 47.1 mpg (Imperial) — impressive by UK standards and typical of efficient turbodiesels sold on the continent.

6 L/100km = 47.08 mpg imp

A mainstream European family hatchback at 8 L/100km converts to 35.3 mpg (Imperial), around average for the UK new-car market.

8 L/100km = 35.31 mpg imp

A Peugeot 208 petrol hybrid at 5 L/100km achieves 56.5 mpg (Imperial) — firmly in the UK's 'excellent economy' bracket for family cars.

5 L/100km = 56.5 mpg imp

A large European SUV at 12 L/100km converts to 23.5 mpg (Imperial), below average for the UK market and typical of heavier petrol vehicles.

12 L/100km = 23.54 mpg imp

mpg to l per 100km l per 100km to mpg kml to mpg mpg to kml

L/100km to MPG (Imperial) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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