Draft article. This page is hidden from search engines until it is reviewed and published.
How to calculate fuel mileage, and why the full-tank method works
A plain explanation of the full-tank method for working out how far your vehicle travels on a litre of fuel.
Fuel mileage is the distance you travel for each unit of fuel. The most dependable way to measure it is the full-tank method, because it does not rely on the fuel gauge, which is only an estimate.
The method
Fill the tank completely and note the odometer reading. Drive as you normally do. At the next fill-up, fill the tank completely again and note the litres added and the new odometer reading. Divide the distance driven since the last fill-up by the litres added.
A worked example
If the odometer moved 420 km between two full fill-ups and the second fill-up took 30 litres, the mileage for that stretch is 14 km per litre. This is an illustration of the arithmetic, not a benchmark for any vehicle.
Why one reading is not enough
A single stretch can be skewed by traffic, a long highway run or a partly filled tank. Several readings in a row show the real pattern, and a sudden change is often the first sign that something needs attention, such as tyre pressure or a service.