MPG to L/100km conversion table

Every whole number from 5 to 100 miles per gallon, converted to litres per 100 km and kilometres per litre, for both the US gallon and the imperial gallon. The US columns use the constant 235.214583 and the UK columns use 282.480936; both are computed from the exact definitions of the gallon and the mile, and every cell is calculated at build time from the same code the converter runs.

Read the row for your mpg figure in the column for your gallon. A British figure of 50 mpg is in the UK column, at 5.65 L/100km; an American figure of 50 mpg is in the US column, at 4.70. The two never share a row because the gallons are different sizes, which the gallon guide explains. For values between whole numbers, or beyond 100, use the converter.

The gaps between rows shrink as mpg rises. From 10 to 11 mpg the US L/100km figure drops by 2.14 litres; from 50 to 51 it drops by 0.09. That is the reciprocal relationship at work, and it is why a one-mpg improvement means ten times more fuel at the bottom of the table than at the top. The MPG or L/100km guide covers what that means when comparing cars.

Common reference points: 20 mpg (US) is 11.76 L/100km, roughly a full-size pickup. 30 mpg (US) is 7.84, a typical petrol sedan. 40 mpg (US) is 5.88, a mild hybrid or a very efficient small car. 50 mpg (US) is 4.70, hybrid territory. On the UK side, 50 mpg is 5.65 L/100km and 60 mpg is 4.71, the two figures most British reviews treat as the line between good and very good.