Gallons Needed
12.00
Fuel Calculator
Calculate trip fuel cost and cost per mile.
Total Fuel Cost
$42.00
Cost per Mile
$0.140
How to use the Fuel Calculator
The Fuel Calculator is free and runs entirely in your browser — no sign-up, and nothing you enter leaves your device. It opens pre-filled with a realistic example, so you can see how it works before replacing any figure with your own; the results update as you type. Press Calculate to refresh the result panel, or Reset to return to the example.
The inputs it asks for:
- Distance (miles) — a number.
- Fuel Economy (MPG) — a number.
- Fuel Price per Gallon — a dollar amount.
The formula
It works out how much fuel a trip needs from your distance and fuel economy, then multiplies by the price per gallon for the total — and divides back out for the cost per mile:
Gallons = Distance ÷ MPG
Cost = Gallons × Price per gallon Cost per mile = Cost ÷ Distance- MPG
- miles per gallon — your vehicle's fuel economy
Real-world economy varies with speed, load, terrain, weather and driving style, so use a realistic MPG — your recent average beats the sticker figure. For an electric vehicle the same logic applies with miles-per-kWh and the price of electricity.
Worked example
Using the example values — Distance (miles) 300, Fuel Economy (MPG) 25, Fuel Price per Gallon $3.50 — the Fuel Calculator returns a Total Fuel Cost of $42.00. It also reports Gallons Needed (12.00), Cost per Mile ($0.140).
Prefer your own numbers? Change any field above and this recomputes instantly.
Key terms
- Fuel economy (MPG)
- Miles travelled per gallon of fuel.
- Cost per mile
- Total fuel cost divided by distance — handy for comparing trips or vehicles.
- Gallons needed
- Distance divided by fuel economy.
Frequently asked questions
What MPG should I enter?
Your recent real-world average, not the window-sticker rating — actual economy is usually lower, especially in city driving or cold weather.
Can I use this for a round trip?
Yes — enter the total distance (both ways). For mixed city/highway driving, use a blended MPG.
Does it work for electric vehicles?
Not directly, but the same idea applies: swap MPG for miles-per-kWh and fuel price for the electricity rate to get cost per mile.