Fuel Economy Calculator
The Fuel Economy Calculator computes fuel economy from the relation liters per 100 km = liters used / distance x 100. It takes 2 inputs (fuel used in liters, distance travelled in km) and returns the fuel economy. Because this is a pure mathematical or physical formula rather than a jurisdiction-specific rule, the result never changes over time: the same inputs always produce the same answer, so you can rely on it whether you are checking homework, sizing a design, or sanity-checking another tool. Enter your values in the fields below and the result updates instantly; you can also share a permalink that pre-fills the exact calculation, which is useful for teaching, reports, or collaboration. For example, with fuel used = 50 liters, distance travelled = 400 km, the fuel economy works out to 12.5, and the worked example further down the page shows every step so you can follow the arithmetic and reproduce it by hand. The method is the standard form documented by US DOE fueleconomy.gov, and the figure above each result carries the date it was last verified. This tool is general information and is not a substitute for professional engineering, medical, financial, or scientific advice; always check critical results against the primary source and your own judgement.
With Fuel used = 50 liters, Distance travelled = 400 km, the result is 12.5.
Applies to: any numeric inputs. Method source: US DOE fueleconomy.gov, checked 2026-06-23.
The formula
liters per 100 km = liters used / distance x 100
Worked example
With Fuel used = 50 liters, Distance travelled = 400 km:
- L/100km = liters / distance x 100
- = 50 / 400 x 100 = 12.50
- Fuel Economy = 12.5
This worked example is one of the automated golden-value tests this calculator must pass before it can publish.
What this assumes
- Inputs are real numbers in the units shown.
- The result is the exact value of liters per 100 km = liters used / distance x 100; general information, not professional advice.
Frequently asked questions
What formula does this use?
liters per 100 km = liters used / distance x 100, the standard form documented by US DOE fueleconomy.gov.
Does the result ever change over time?
No. This is a pure formula with no external rate, so the same inputs always give the same result.
Official sources and verification
- Method: US DOE fueleconomy.gov, checked 2026-06-23.
Reviewed by the CalculatorHub team, edited by James Graham, 2026-06-23. See our methodology. General information, not professional advice.