A worked example
A 500-mile trip at 25 mpg and $3.50 per gallon needs 20 gallons of fuel — exactly $70.
Frequently asked questions
Why might my actual fuel cost differ from this estimate?
Highway speeds, headwinds, AC use, a loaded vehicle, and aggressive driving can all push real-world fuel economy below the EPA-rated figure — actual costs commonly run 10-20% higher than calculations based on the sticker mpg.
How can I find my vehicle's actual mpg instead of guessing?
Use the Gas Mileage Calculator with data from a recent fill-up — tracking your own real mileage gives a more accurate number than relying on advertised EPA figures.