Trip Gas Cost Calculator
Estimate the fuel cost of a road trip from the distance, your vehicle’s fuel economy and the price at the pump.
How it works
Gallons = distance ÷ mpg · Cost = gallons × price per gallon
Fuel needed is the trip distance divided by your car’s miles-per-gallon, and the cost is that gallon count multiplied by the pump price. Highway driving usually beats the EPA combined rating while city stop-and-go falls below it, so use your real observed economy for the best estimate. A loaded car, roof box, or headwind can cut economy by 10–20%, nudging the true cost above this figure.
Worked example
A 300-mile one-way trip in a car that gets 28 mpg needs 300 ÷ 28 = 10.71 gallons. At $3.50 a gallon that is 10.71 × 3.50 = $37.50, or about $0.125 per mile.
Frequently asked questions
What fuel economy number should I use?
Use your car’s real-world average from the trip computer or from tracking a few fill-ups, not the sticker figure. Steady highway cruising often exceeds the EPA rating while city driving comes in under it.
Does this include tolls or wear?
No — this is fuel only. Add tolls, parking and a per-mile allowance for maintenance and depreciation if you want the full cost of driving.
How do I estimate for an electric car instead?
This tool assumes a gas vehicle. For an EV, cost depends on kWh used and your electricity rate rather than gallons and pump price, so use a dedicated EV road-trip cost tool.
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This calculator is for educational purposes. Double-check important results before acting on them.