Vehicle & Fuel Calculators

About these calculators

Four calculators cover running costs and tyre fitment. Fuel Cost Calculator turns a trip distance, your mileage and the fuel price into fuel needed, trip cost and cost per kilometer or mile, in metric, US or UK units, with a one-way or round-trip switch. Fuel Average Calculator works out your real fuel economy from the distance and fuel used, or from odometer readings at the start and end of a tank, and shows it as km/L, L/100 km, US MPG and UK MPG together. EV Charging Cost Calculator starts from the distance you drive and your car's efficiency, or from the kilowatt-hours you add, then allows for charging losses and prices the electricity you draw from the grid.

Tyre Size Comparison takes two sizes written like 205/55R16 and 225/45R17 and compares overall diameter, sidewall height, circumference and revolutions per kilometer, then shows what the speedometer would read compared with true speed. These are arithmetic estimates from the figures you enter. They do not measure real fuel use on a given road, and they assume steady prices and a steady charging loss. The tyre tool works only from the nominal size, so it does not know how much a tyre actually flexes under load, whether it fits your wheel arch, or whether it is approved for your vehicle. For converting an existing figure between MPG and L/100 km, the Fuel Economy Converter in the Unit Conversion category does just that. Each page shows its formula with a worked example, and the calculations run in your browser.