Fuel Trip Cost Calculator
Estimate how much gas a road trip will cost — total, per person, and gallons burned.
How it works
gallons = distance ÷ MPG · cost = gallons × price per gallon · per person = cost ÷ people
The trip distance divided by your fuel economy gives the gallons the trip consumes; multiplying by the pump price gives the dollar cost. Splitting divides the total evenly among everyone in the car. Use your real-world MPG rather than the window-sticker number — loaded cars on the highway with AC running usually land a little below it.
Worked example
A 400-mile trip at 28 MPG uses 400 ÷ 28 = 14.3 gallons. At $3.50 per gallon that’s $50.00 in gas — $25.00 each with two people sharing, or about 12.5¢ per mile.
Frequently asked questions
How should we split if someone rides only part of the way?
Split by miles ridden: cost per mile × the miles each person was in the car. This calculator’s per-mile figure makes that a one-step multiplication.
Is gas the whole cost of the trip?
No — tires, oil and depreciation add up too. The IRS all-in mileage rate (70¢/mile for 2025) is a fair proxy for the true per-mile cost, roughly five times the gas-only number for an average car.
What MPG should I use for a highway road trip?
Use the EPA highway figure minus 5–10% for real conditions, or check your trip computer. Roof boxes, heavy loads and speeds over 70 mph can each shave several MPG.
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This calculator is for educational purposes. Double-check important results before acting on them.