Fuel Cost Calculator
Estimate what a drive will cost in gas. Enter the distance, your vehicle's MPG, and the price per gallon — toggle round trip to double it.
Price is always per US gallon — the standard U.S. gas-price quote, even when using UK mpg above.
Efficiency vs 27 mpg avg
How you compare
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Check it outPlan a drive's cost
Fuel cost is distance divided by miles per gallon, times the price of gas. Highway driving usually beats your car's city MPG, while heavy loads, mountains, and aggressive driving cut it. For a road trip, toggle round trip and split the total among passengers to see the real per-person cost.
How it’s calculated
Gallons = distance ÷ MPG. Cost = gallons × price per gallon (× 2 for a round trip).
A UK (imperial) gallon is 1.20095× a US gallon, so the same real fuel efficiency reads as a higher "UK mpg" number than "US mpg." Choosing UK mpg divides your entered figure by 1.20095 to get the US-mpg equivalent used in the gallons formula above; the price per gallon field always means US gallons, the standard U.S. gas-price quote. If you enter trips per year, the estimated annual fuel cost is simply the per-trip cost (already doubled if round trip is on) × trips per year.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Worked example
A 300-mile drive at 28 mpg and $3.50/gallon uses ~10.7 gallons, about $37.50.
Common mistakes
- Using city MPG for a highway trip (or vice versa).
- Forgetting to double it for a round trip.
Frequently asked questions
What MPG should I use?
Use your car's real-world average if you track it; otherwise the EPA combined rating is a fair estimate.
Does this work for electric vehicles?
Not directly — it's built for gallons. For EVs, you'd calculate kWh used times your electricity rate instead.
How do I split a road trip cost?
Take the total fuel cost and divide by the number of people sharing the ride.