Fuel Economy Converter
Convert MPG, L/100km, and km/L.
Fuel economy, converted
Efficiency is measured as distance per fuel (MPG, km/L) or fuel per distance (L/100km), and they run in opposite directions. Thirty US MPG is about 7.8 L/100km — a lower L/100km is better.
It is essential when comparing cars sold in different markets, since a US window sticker in MPG and a European one in litres per 100 km cannot be compared until they share a unit.
US vs imperial gallon
A US gallon is smaller than an imperial one, so UK MPG figures look higher for the same car. The math runs locally in your browser. The math runs on your device with nothing uploaded.
Frequently Asked Questions
How does the fuel economy converter work?
Fuel economy is reciprocal: higher mpg means lower liters per 100 km. US mpg converts with 235.214583 divided by mpg.
When should I use this converter?
Use it to compare car listings, road-trip estimates, international vehicle specs, and fuel efficiency claims.
What is the main limitation?
US and UK gallons differ, so pick the right mpg source before comparing vehicles.
Is this converter private?
Yes. The conversion runs entirely in your browser, so your values are not uploaded, stored, or sent to a server.
More free browser utilities for conversion, formatting, and technical cleanup.