How do I convert mpg to L/100km?

Divide 235.215 by the US miles per gallon figure to get litres per 100km. For imperial mpg, divide 282.481 instead. The relationship is inverse, since one measures distance per fuel and the other fuel per distance.

What does New Zealand use for fuel economy?

New Zealand uses litres per 100 kilometres, where a lower number is better. A typical small car is around 6 to 8 litres per 100km.

Are US and imperial gallons the same?

No. An imperial gallon is larger than a US gallon, so imperial mpg figures look better for the same real economy. The converter handles both.

Fuel Economy Converter

This fuel economy converter changes a vehicle's efficiency between the different ways it is measured around the world, which is more confusing than most unit conversions because the units do not all run the same way. New Zealand, like most of the world, uses litres per 100 kilometres, where a lower number means a more efficient car. The United States and some older or imported figures use miles per gallon, where a higher number is better, and to add to the muddle the US gallon and the imperial gallon are different sizes, so the same car has a higher imperial mpg than US mpg. Kilometres per litre is another distance-per-fuel measure sometimes seen. You enter a value, pick the unit it is in and the unit you want, and the converter handles the inverse relationship for you: distance-per-fuel units like mpg and km per litre go up as efficiency improves, while fuel-per-distance units like litres per 100km go down. This makes it easy to judge an imported car advertised in mpg against the New Zealand standard, or to compare two cars quoted in different units. As a guide, a frugal small car is around 6 litres per 100km, which is roughly 39 US mpg. Enter a value and choose your units to convert fuel economy straight away.

How it works

The converter turns your value into litres per 100km as a common base, then into the unit you want. Because miles per gallon and kilometres per litre measure distance per unit of fuel, they relate to litres per 100km by an inverse, not a simple multiply, which the calculator handles automatically.

Worked example

A car using 7 litres per 100km converts to US miles per gallon as 235.215 divided by 7, which is about 33.6 US mpg, or about 40 imperial mpg.

Related calculators

Fuel Consumption Calculator: work out your real economy.
Fuel Cost Calculator: cost of a trip.
Unit Converter: length and volume.
Vehicle Running Cost Calculator: total running cost.

Calculate.co.nz is partnered with Interest.co.nz for New Zealand's highest quality calculators and financial analysis.

All calculators and tools are provided for educational and indicative purposes only and do not constitute financial advice.

Calculate.co.nz is proudly part of the Realtor.co.nz group, New Zealand's leading property transaction literacy platform, helping Kiwis understand the home buying and selling process from start to finish. Whether you're a first home buyer navigating your first property purchase, an investor evaluating your next acquisition, or a homeowner planning to sell, Realtor.co.nz provides clear, independent, and trustworthy guidance on every step of the New Zealand property transaction journey.

Calculate.co.nz is also partnered with Health Based Building and Premium Homes to promote informed choices that lead to better long-term outcomes for Kiwi households.

All content on this website, including calculators, tools, source code, and design, is protected under the Copyright Act 1994 (New Zealand). No part of this site may be reproduced, copied, distributed, stored, or used in any form without prior written permission from the owner.