Everyday
Gas Mileage and Fuel Economy Calculator
Calculate miles per gallon, litres per 100 kilometres, trip fuel, and trip cost from distance and fuel used. The calculator uses MPG = miles ÷ gallons; L/100 km = litres ÷ kilometres × 100. It returns more than one result so you can check the main answer against a useful secondary measure. Lower L/100 km is more efficient, while higher MPG is more efficient. Tank-fill errors, idling, weather, towing, and route mix can move short-sample results.
Check the displayed units, assumptions, and rounding before relying on the result.
Calculate and compare
Use the number box for precision or the slider for fast scenario testing.
Scenario results
Fuel economy
8.571 L/100 km
Litres used per 100 kilometres.
US MPG equivalent
27.442 mpg
Converted from L/100 km.
Planned trip fuel cost
$112.93
Estimated fuel: 72.86 L.
How the calculation works
Use consistent units and retain full precision until the final display step.
Worked example
Reproduce the displayed scenario, then change one assumption at a time.
Assumptions behind the result
- • Inputs use the units shown beside each control.
- • The displayed formula is applied without hidden market or demographic data.
- • Rounding occurs only for display; calculations keep full numeric precision.
- • Lower L/100 km is more efficient, while higher MPG is more efficient.
- • Tank-fill errors, idling, weather, towing, and route mix can move short-sample results.
Mistakes that change the answer
- • Mixing percentages with decimals or mixing incompatible units.
- • Relying on a rounded intermediate value instead of the full result.
- • Changing several assumptions at once instead of testing distance traveled separately.