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Fuel Economy Converter

Convert between mpg, km/l, and litres/100 km.

Free to use, no sign-up required. Fuel Economy Converter is one of 198 tools built into Xenition, alongside a chat that can use them for you.

Converts fuel economy between litres per 100 km, km per litre, US mpg, UK mpg and miles per litre. Use it to compare cars reviewed in different countries.

How to use Fuel Economy Converter

1. Enter the figure in the left box.
2. Choose its unit — it starts on mpg (US).
3. Choose the unit you want — it starts on L/100km.
4. Read the result, rounded to two decimals, and mind the note under the tool: for L/100km, lower is better.

How it works

This is not a simple ratio, because L/100km is fuel per distance and the others are distance per fuel. Every figure goes through L/100km: L/100km = 235.214583 ÷ US mpg, 282.480936 ÷ UK mpg, 100 ÷ km/L, or 62.1371192 ÷ mi/L. Zero and negative values give no answer.

Example

A car rated 30 mpg (US) uses 7.84 L/100km. The same car is 36.03 mpg (UK) and 12.75 km/L.

Questions about Fuel Economy Converter

Why do UK mpg figures look better than US ones?

A UK gallon is 4.546 litres and a US gallon 3.785 litres, so a car goes about 20% further on a UK gallon. The same car is 30 mpg in the US and 36 mpg in the UK.

Why is improving a thirsty car worth more than improving an efficient one?

Fuel used is the inverse of mpg. Going from 20 to 40 mpg (US) saves 5.88 L per 100 km; going from 40 to 60 mpg saves only 1.96 L. That is why many countries rate cars in fuel per distance.

Use it from chat

You do not have to open Fuel Economy Converter to use it. Ask Xenition in plain language and it runs the right tool, then carries the answer into whatever you are working on — a document, a spreadsheet, a deck.

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