Formula
The trip length is the difference of the odometer:
MPG = (ending miles − starting miles) / gallons
Cost per mile is the fill-up cost divided by those miles, rounded to the nearest cent. The fuel economy page starts from a distance you type and converts the units. It does not price the mile.
Assumptions
- The gallon is the US gallon.
- The tank was filled to the same mark both times.
- The price is per gallon, and currency changes the symbol only.
Worked example
From 12,000 to 12,360 miles on 12 gallons is 30 mpg. At $3.50 a gallon that is $0.12 per mile.
Input definitions
- Odometer
- The cumulative miles at the start and end of the tank.
- Gallons added
- The fuel required to return the tank to the same mark.
Limitations
This is one tank, not a laboratory cycle. It is not a forecast for the next trip.
Questions
Why a second miles-per-gallon page?
The fuel economy page converts one distance and one fuel amount into three unit systems. This page uses two odometer readings and adds a cost per mile.
Does the currency convert the fuel price?
No. Type the price in the currency you paid.