MPG Calculator
Calculate miles per gallon from miles driven and gallons used, plus cost per mile and yearly fuel cost.
How it works
MPG = miles ÷ gallons · Cost per mile = fill cost ÷ miles · Yearly cost = (annual miles ÷ MPG) × price per gallon
Miles per gallon is just the distance covered divided by the fuel it took. Feeding in what you paid at the pump turns that into a cost per mile, and applying it to a full year of driving projects your annual fuel bill. Where a gas mileage calculator typically works from two odometer readings, this one folds in what you spent and scales it out to a yearly cost.
Worked example
Driving 350 miles on 12.5 gallons is 28.0 MPG. A $43.75 fill works out to $3.50 a gallon, about $0.125 per mile, or roughly $1,500 a year at 12,000 miles.
Frequently asked questions
What is the most accurate way to measure MPG?
Fill the tank completely, reset the trip meter, drive normally, then refill and divide the trip miles by the gallons it took to top off. One tank can be skewed by driving conditions, so average several.
How is this different from a gas mileage calculator?
A gas mileage calculator usually asks for starting and ending odometer readings. This tool takes miles and gallons directly and adds cost per mile plus a yearly fuel-cost projection.
Why did my MPG drop?
Cold weather, short trips, low tire pressure, roof racks, aggressive acceleration and heavy loads all cut fuel economy. A sudden, lasting drop can also flag a maintenance issue worth checking.
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This calculator is for educational purposes. Double-check important results before acting on them.