Fuel Efficiency Calculator
Calculate your real-world fuel economy from distance travelled and fuel used.
What the Fuel Efficiency Calculator does
Fuel efficiency is measured two opposite ways. Litres per 100 km is a consumption measure where lower is better; miles per gallon is a distance measure where higher is better. Both describe the same thing.
Formula
L/100km = (Litres ÷ Kilometres) × 100km/L = Kilometres ÷ LitresUS mpg = 235.215 ÷ L/100km
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Distance travelled | number | Yes | Accepts more than 0. |
| Distance unit | one of 2 options | Yes | — |
| Fuel used | number | Yes | Accepts more than 0. |
| Fuel unit | one of 3 options | Yes | — |
| Fuel price per unit | selected currency | Optional | Optional — shows running cost. Accepts 0 or more. |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose Distance unit and Fuel unit.
- Enter Distance travelled and Fuel used.
- Optionally add Fuel price per unit.
- Select Calculate.
Worked example
620 km travelled using 42 litres.
- Distance
- 620
- Fuel
- 42
- Unit
- Litres
6.77 L/100 km, 14.76 km/L, or 34.7 US mpg.
Frequently asked questions
Why does my efficiency vary between tanks?
Driving style, traffic, temperature, tyre pressure and load all affect it. Average several tanks for a reliable figure.