Gas Mileage Calculator

Gas mileage (or fuel economy) measures how efficiently a vehicle uses fuel. In the US, this is miles per gallon (MPG); in the UK, also MPG but using the larger imperial gallon; in most other countries, litres per 100km (L/100km)

The calculator uses the standard published formula for gas mileage. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches, kilometres, miles, litres. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: MPG = Miles driven / Gallons used. Each step in the calculation is shown so you can verify the result manually.