mpg to l/100km converter
Use this converter to turn mpg to l/100km and back, or to km/l. A car using 6.5 l/100km does 36.19 mpg (US gallon), 43.46 mpg (imperial gallon) and 15.38 km/l. With a 50 litre tank it reaches 769 km.
Example: Fuel economy value 6.5 · Convert from: l/100 km · Convert to: mpg (US gallon) · Tank size (optional) 50 l → Result: 6.5 l/100 km = 36.187 mpg (US). Source: Wikipedia – Fuel economy in automobiles: converting between L/100 km and miles per gallon (235.215 and 282.481). Updated: .
How it is calculated
mpg to l/100km – the formulas
Litres per 100 kilometres and miles per gallon measure the same thing in opposite directions: fewer litres means more miles. So the conversion is a reciprocal: mpg (US) = 235.215 ÷ l/100 km and mpg (UK) = 282.481 ÷ l/100 km. The same numbers convert back: 30 mpg (US) is 235.215 ÷ 30 = 7.84 l/100 km. For km/l use km/l = 100 ÷ l/100 km.
Where the numbers come from
They follow from the definitions: 1 mile = 1.609344 km, 1 US gallon = 3.785411784 l and 1 imperial gallon = 4.54609 l. For example 100 × 3.785411784 ÷ 1.609344 = 235.2146.
US mpg and UK mpg
- US gallon: 3.785 l, used in the United States.
- Imperial gallon: 4.546 l, used in the United Kingdom. The mpg figure is therefore about 20% higher.
- Plain “mpg” means US mpg in the United States and UK mpg in Britain.
Limits
The conversion is exact, but the fuel economy itself is not: manufacturer figures (WLTP, EPA) and everyday consumption often differ a lot. The range is a calculation at constant consumption, not a promise.
Frequently asked questions
How do you convert mpg to l/100km?
Divide 235.215 by the mpg value for US gallons, or 282.481 for imperial gallons. 30 mpg (US) is 7.84 l/100 km.
What is 30 mpg in l/100km?
30 mpg (US) equals 7.84 l/100 km, and 30 mpg (UK) equals 9.42 l/100 km.
How do you convert km/l to l/100 km?
Divide 100 by km/l. 15 km/l is 6.67 l/100 km, and the other way round.
Is a high or a low number better?
For l/100 km a low number is better, for mpg and km/l a high one.
Why are US and UK mpg different?
Because the gallons differ in size: 3.785 l in the US and 4.546 l in the UK.
Sources and legal basis
- Wikipedia – Fuel economy in automobiles: converting between L/100 km and miles per gallon (235.215 and 282.481)
- NIST SP 811 – Guide for the Use of the International System of Units: conversion factors (mile, gallon)
As of: · Editorial policy
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