Fuel Trip Cost Calculator
Enter any two of distance (mi), gallons, and MPG to solve for the third. Optionally add price per gallon or total paid at the pump for an approximate trip cost. Works for gasoline, diesel, or ethanol: use the price and economy for the fuel your car actually burns.
Your leg in numbers
Optional cost
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Summary
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Fuel
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Real-world economy varies with load, tyres, and road.
How to use it
The tool ties together three road-trip quantities: how far you drive in miles, how many gallons that takes, and your car's MPG.
- Estimate or measure MPG for the car and driving style you care about.
- Enter any two of distance (mi), gallons, and MPG. Keep the third at zero if you want it calculated.
- Add price per gallon if you want an estimated cash cost, or enter what you paid and the gallons bought to back out an effective price per gallon.
- Press Calculate. If all three physics values are filled, they must agree within a small tolerance or the form will ask you to review them.
What sits behind the numbers
With distance D in mi, volume V in gallons, and economy E in MPG:
Money lines are simple once you trust the volume in gallons:
When it helps
Rough budgets before a drive, quick checks after a fill-up, or classroom-style sanity checks on dashboard figures all use the same relationships. The page does not know your real-time traffic, terrain, or idle time, so treat outputs as planning hints rather than invoices.
Limits
Economy swings with load, tyres, speed, and weather. A single km/L or MPG guess is only as good as the driving it represents. Prices and pump totals are whatever you type. The site does not fetch live station prices.
FAQ
Why zero in the fields?
Zero means “not using this value as an input”. The calculator treats non-positive entries as missing so you can leave one physical quantity blank on purpose.
Do I have to enter a price?
No. Leave price and total paid at zero if you only want litres, distance, or implied economy.
How do I get price per litre from a receipt?
Enter the total you paid and the litres on the receipt, with price per litre still at zero. Add average km/L if distance is still unknown.
Does it work for gasoline, diesel, and ethanol?
Yes. The math is the same for any fuel at the pump. Use the price and average economy for the fuel your car actually burns on that stretch.