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 DVLA figures use Imperial mpg, so use this number when estimating running costs. At UK diesel prices, 39 mpg is reasonable for a family car.

Why is the conversion factor 282.481 instead of 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 km/mile = 235.214. For Imperial gallons (4.546 L): 4.546 × 100 ÷ 1.60934 = 282.481. The larger Imperial gallon means you 'travel further per gallon', giving a bigger number.

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

Very close. 282.481 ÷ 5.1 = 55.4 mpg (Imperial). Yes, they are effectively the same vehicle — the small difference is rounding. Always check whether UK mpg figures are 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 official standard for fuel economy labelling.

Liters per 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? European manufacturers publish consumption in liters per 100 kilometers, while the UK and many Commonwealth countries use miles per Imperial gallon. The Imperial gallon (4.546 liters) is 20% larger than the US gallon, which is why mpg (Imperial) figures always look more impressive than mpg (US) for the same car. The conversion factor 282.481 comes from the exact relationship between Imperial gallons and kilometers. 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.

Source: NIST SP 811, Table B.8

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 in Europe.

6 L/100km = 47.08 mpg imp

A mainstream 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 hybrid or small diesel at 5 L/100km achieves 56.5 mpg (Imperial) — solidly in the UK's 'excellent economy' bracket.

5 L/100km = 56.5 mpg imp

A large 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

Liters per 100km to MPG (Imperial) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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