FUEL ECONOMY AND TRIP COST

Fuel Cost Calculator

Estimate miles per gallon, gallons per 100 miles, cost per mile, and the fuel cost of a planned trip from distance, fuel used, and price per gallon.

How fuel economy is calculated

Miles per gallon is distance divided by fuel used. Gallons per 100 miles is the inverse expression used for a 100-mile stretch. Both come from the same fill-up record when distance and gallons belong to the same period.

MPG = miles ÷ gallons
Gallons per 100 miles = gallons ÷ miles × 100
Cost per mile = gallons × price ÷ miles
Trip fuel cost = trip miles ÷ MPG × price

Example

300 miles on 12 gallons is 25 MPG, or 4 gallons per 100 miles. At $3.50 a gallon, each mile costs $0.14, and a 120-mile trip uses about $16.80 of fuel.

What the trip cost leaves out

Traffic, short trips, cargo, tire pressure, hills, and driving style change real consumption. Parking, tolls, maintenance, and depreciation are not included. The gallon unit is the US liquid gallon used at US pumps.

Frequently asked questions

Should the tank size go in the gallons field?

No. Enter the fuel actually used for the recorded miles, such as the gallons added at the next fill-up.

Is a higher MPG always better?

For the same vehicle and conditions, a higher MPG means more distance per gallon. Gallons per 100 miles move in the opposite direction.

Can I use kilometers?

This English page uses miles and US gallons. Convert the inputs first, or use the unit converter.

Does trip cost include tolls?

No. It estimates fuel only.

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