How to calculate fuel cost
Cost = (miles ÷ MPG) × price per gallon
Worked example. Trip fuel cost: $43.13.
Example inputs — Trip distance (miles): 350 mi; Fuel economy (MPG): 28 mpg; Gas price per gallon: $3.45; Trip type: One way. Starting values are illustrative.
From George Guju, founder of Calculyn · Educational calculator guidance, not professional advice.
How it works
Divide the distance by your car's miles per gallon to get gallons used, then multiply by the price per gallon.
Assumptions & limitations
- Real fuel economy varies with speed, load, weather and driving style.
Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators
Frequently asked questions
How do I find my MPG?
Use the MPG calculator: fill up, reset your trip meter, and divide miles driven by gallons at the next fill-up.