YOUR MPG IS A NUMBER. MAKE SURE IT IS YOURS.
How to Calculate MPG
MPG is miles driven divided by gallons used on a full-tank cycle. Here is the formula and how to avoid common mistakes.
By Gas Tracker Editorial · Published 2026-01-15 · Updated 2026-03-01
Short answer
MPG = miles driven ÷ gallons used for a given tank (or several consecutive full tanks). Use odometer readings between fill-ups and gallons from the pump.
The MPG formula
- Fill the tank completely and note the odometer (or reset trip meter).
- Drive normally until the next full fill-up.
- Record gallons pumped at the second fill-up.
- Divide miles driven by those gallons.
Example: 312 miles on 11.2 gallons → 27.9 MPG.
What counts as a good MPG?
It depends on your vehicle class. Compare against your own history and EPA estimates for your model year — not against unrelated cars.
Why MPG changes
Traffic, weather, tire pressure, cargo, A/C use, and short trips all move real-world MPG. A single tank can mislead; trends matter more.
MPG vs L/100km
US drivers use MPG (higher is better). Many countries use liters per 100 km (lower is better). See our MPG vs L/100km guide.
Track it automatically
Tired of calculating manually? Gas Tracker AI updates MPG from your logged fill-ups when you record odometer readings.
Try the MPG Calculator for a quick one-off calculation.