Driving
Fuel used
Efficiency is in the denominator, so improving it reduces the fuel used and the cost.
The Formula
gallons = miles / miles per gallon
Efficiency is in the denominator, so improving it reduces the fuel used and the cost.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| g | Gallons used | gallons | Fuel consumed on the journey. |
| m | Miles | miles | Distance driven. |
| e | Efficiency | mpg | Miles per gallon for the vehicle. |
What Each Symbol Means
ggallons
Gallons used
Fuel consumed on the journey.
mmiles
Miles
Distance driven.
empg
Efficiency
Miles per gallon for the vehicle.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate a cost per mile page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate A Cost Per Mile, filed under Everyday Life. Every number the guide produces comes from substituting into this one line.