By clicking a retailer link you consent to third-party cookies that track your onward journey. This enables W? to receive an affiliate commission if you make a purchase, which supports our mission to be the UK's consumer champion.

Litres to gallons converter

Our free tool converts between litres and gallons, so you can see exactly how much fuel it takes to fill your tank
Dino BurattiResearcher & writer
Petrol pumps at forecourt

Fuel economy is typically measured by miles to the gallon, but at the fuel pump petrol and diesel is measured in litres. Using our free tool, you can convert between the two so you can more accurately judge your car's fuel economy.

Which? car mpg tests discover a car’s true mpg by using a rolling road in a lab, which means every car can be tested in the exact same way, and the same environment. 

The test roads imitate city, out-of-town and motorway driving for extended periods of time - something the official tests don't do - which allows you to see how the mpg could affect your pocket depending on the roads you typically drive on.  

Looking to cut your running costs? We show you how in our money-saving driving tips guide.

Litres to gallons converter

Thinking about buying an electric car? We show you how much electric cars cost to charge in our guide

Which? Car Survey 2025

Which? Car Survey 2025: now open

Tell us about your car and be in with a chance of winning £2,500 (T&Cs apply).

Take part now

Check your petrol prices

Our tests reveal that most official fuel-economy figures are inaccurate.

To discover your car’s true mpg, try using the Which? car fuel calculator. It allows you to work out the amount of fuel you used on recent trips, and see exactly how much you ended up paying for single journeys.

Compare car insurance

Find the right policy for your vehicle using the service provided by Confused.com

Get a quote now

Driver calculators and tools

About Us

Which? Limited is registered in England and Wales to 2 Marylebone Road, London NW1 4DF, company number 00677665  and is an Introducer Appointed Representative (FRN 610689) of the following:


1. Inspop.com Ltd for the introduction of non-investment motor, home, travel and pet insurance, who are authorised and regulated by the Financial Conduct Authority (FCA) to provide advice and arrange non-investment motor, home, travel and pet insurance products (FRN310635). Inspop.com Ltd is authorised and regulated by the Financial Conduct Authority (FCA) to provide advice and arrange non-investment motor, home, travel and pet insurance products (FRN310635) and is registered in England and Wales to Greyfriars House, Greyfriars Road, Cardiff, South Wales, CF10 3AL, company number 03857130. Confused.com is a trading name of Inspop.com Ltd. 


2. LifeSearch Partners Limited (FRN656479), for the introduction of Pure Protection Contracts and Private Health Insurance, who are authorised and regulated by the FCA to provide advice and arrange Pure Protection Contracts and Private Health Insurance Contracts.  LifeSearch Partners Ltd is registered in England and Wales to 3000a Parkway, Whiteley, Hampshire, PO15 7FX, company number 03412386.


3. HUB Financial Solutions, for the introduction of equity release advice and an annuity comparison service, who are authorised and regulated by the Financial Conduct Authority (‘FCA’) to provide advice and guidance on financial products for those who have retired or are approaching retirement (FCA Firm Reference Number: 455713). HUB Financial Solutions is registered in England and Wales to Enterprise House, Bancroft Road, Reigate, Surrey RH12 7RP, company number 05125701.


4. Alan Boswell Insurance Brokers Ltd (FRN 301), for the introduction of non-investment landlord insurances, who are authorised and regulated by the Financial Conduct Authority to provide advice and arrange insurance contracts. Alan Boswell insurance brokers Ltd is registered in England at Prospect House, Rouen Rd, Norwich NR1 1RE, company number 02591252.


Other financial services:

Mortgage service provided by London & Country Mortgages (L&C), Unit 26 (2.06), Newark Works, 2 Foundry Lane, Bath BA2 3GZ. London & Country are authorised and regulated by the Financial Conduct Authority (registered number: 143002). The FCA does not regulate most Buy to Let mortgages. Your home or property may be repossessed if you do not keep up repayments on your mortgage.


We do not make, nor do we seek to make, any recommendations or personalised advice on financial products or services that are regulated by the FCA, as we’re not regulated or authorised by the FCA to advise you in this way. In some cases, however, we have included links to regulated brands or providers with whom we have a commercial relationship and, if you choose to, you can buy a product from our commercial partners. 


If you go ahead and buy a product using our link, we will receive a commission to help fund our not-for-profit mission and our campaigns work as a champion for the UK consumer. Please note that a link alone does not constitute an endorsement by Which?.