How to calculate fuel cost
Gallons = miles ÷ MPG. Fuel cost = gallons × price per gallon. A 300-mile drive each way in a car that gets 28 MPG uses about 21.4 gallons for the round trip; at $3.20 a gallon that is about $68.57.
Use the MPG you actually get, not the sticker figure. Highway driving usually gets more miles per gallon than city driving, and a full car or roof box gets fewer.
The formulas behind it
Every result cell is a plain spreadsheet formula, so you can check the math or rebuild it yourself.
| Cell | Result | Formula |
|---|---|---|
| B9 | Total miles | =B2*B3 |
| B10 | Gallons of gas | =B9/B4 |
| B11 | Fuel cost | =B10*B5 |
| B12 | Cost per person | =B11/B6 |
| B13 | Fuel cost per mile | =B5/B4 |