MPG Calculator
Calculate your car's miles per gallon from miles driven and gallons used, and see your fuel cost per mile, per trip and per year.
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About the MPG Calculator
Your miles per gallon (MPG) shows how far your vehicle travels on one gallon of fuel. To measure it, fill the tank, reset the trip meter, drive normally, then refill and divide the miles by the gallons added. This calculator also turns MPG into the fuel cost per mile, per trip and per year at your local gas price.
How to use it
- Enter the miles driven and the gallons used to refill the tank.
- Enter the gas price, a trip distance and your yearly mileage.
- Press Calculate MPG to see fuel economy and fuel costs.
MPG formula
MPG = miles driven ÷ gallons of fuel used. 312 miles on 11.4 gallons is about 27.4 MPG. Cost per mile = gas price ÷ MPG.
Ways to improve gas mileage
- Keep tires inflated to the recommended pressure.
- Avoid hard acceleration and braking.
- Remove roof racks and extra weight.
- Use cruise control on highways.
- Keep up with maintenance such as air filters and oil.
Frequently asked questions
How do I calculate MPG?
Divide the miles you drove by the gallons of gas you used. Fill up, record the odometer, drive, then fill up again and note the gallons.
What is a good MPG?
Many modern sedans average 28 to 35 MPG combined, hybrids 45 or more and large trucks 17 to 22.
How do I calculate gas cost for a trip?
Divide the trip miles by your MPG to get gallons, then multiply by the gas price.
Does MPG change with speed?
Yes. Most cars are most efficient at moderate steady speeds and use more fuel at high speeds.
How is MPG different from L/100 km?
L/100 km is liters per 100 kilometers. Higher MPG means better economy, while lower L/100 km means better economy.
Last reviewed: November 2026.