Global Fuel CalculatorMPG Calculator — Miles Per Gallon, US and Imperial
This MPG calculator works out miles per gallon from a trip odometer reading and a fill-up, in both US and imperial gallons — the two are not interchangeable, and treating them as if they were is the single most common fuel-economy mistake. The result also includes cost per mile and the L/100km equivalent for comparing against a European or Canadian specification.
MPG works the same way whether the vehicle is a compact car, a truck, or you are averaging several tanks together for a combined figure. What changes between vehicles is only the number, not the method: miles driven divided by gallons used, converted at the end into whichever gallon you actually mean.
Work out your numbers
Common questions
How do I calculate my MPG?
Fill the tank, reset the trip odometer, drive until you need fuel again, then fill to the same cut-off. Divide the miles shown by the gallons it took to refill. 312 miles on 11.4 gallons works out to about 27.4 MPG.
Is 20 MPG a lot?
For a typical passenger car, no — modern compact and mid-size vehicles usually exceed that. For a full-size truck, an older SUV, or a vehicle towing a load, 20 MPG can be entirely normal. What matters more than the absolute number is whether your own figure is trending down over time, which usually points to a maintenance issue rather than the vehicle itself.
How do I calculate fuel cost from MPG?
Divide the trip distance by your MPG to get gallons needed, then multiply by the price per gallon. This calculator does that step automatically once you enter distance, MPG (or the fuel and distance used to derive it) and price.
How do I calculate the fuel cost for a trip using MPG?
Enter your established MPG, the current price per gallon, and your trip distance in the optional field. The calculator returns the gallons the trip will use and the total dollar cost, based on your own measured fuel economy rather than an assumed average.
What is a combined MPG figure?
It is a single number that blends city and highway driving, usually weighted toward how most owners actually drive rather than a straight average of the two. If you average several of your own tanks that mix commuting and longer drives, you are effectively producing your own combined figure.
How do I convert MPG to L/100km?
For US gallons, divide 235.21 by the MPG figure. For imperial gallons, divide 282.5 by it. This calculator shows the L/100km equivalent automatically next to your MPG result, so no manual conversion is needed.