MPG Calculator
Real fuel economy from your own fill-ups.
Enter your values
ⓘ Live results
Results
- Fuel economy
- 30 mpg
- Litres per 100 km
- 7.84
- Kilometres per litre
- 12.75
- Imperial mpg
- 36.03
Working
- 1MPG = 342 ÷ 11.4 = 30
Quick answer
Fuel economy is miles driven divided by gallons used between two full fill-ups.
MPG = miles ÷ gallons
How to use the MPG Calculator
- 1Fill the tank and reset the trip meter.
- 2At the next fill-up, note the miles and gallons.
- 3Enter both to get true economy.
Worked example
Using the values the calculator loads with:
Inputs
- Miles driven342 miles
- Gallons to refill11.4 gal
Results
- Fuel economy30 mpg
- Litres per 100 km7.84
- Kilometres per litre12.75
- Imperial mpg36.03
- MPG = 342 ÷ 11.4 = 30
Frequently asked questions
Why is my mpg worse in winter?
Cold engines run rich, winter fuel blends carry less energy, and heaters and denser air all reduce economy by 10–20%.
What is UK mpg?
Imperial mpg, based on the larger imperial gallon, so it reads about 20% higher than the US figure for the same car.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.