We measure economy by miles to the gallon, but we measure in litres at the fuel pump - here you can convert between the two so you can more accurately judge your car's fuel economy.
The test roads imitate city, out-of-town and motorway driving - something that 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.
If your car is efficient to drive but has taken a few dings in its time, try using one of our and get it back to looking its best. We also tested to see if WD-40 can hide car scratches as several online videos claim.
Our tests reveal that many car trip computers give inaccurate fuel-economy readings.