Gas MPG formula
MPG = miles driven divided by gallons used.
If you drove 300 miles and added 10 gallons at the next fill-up, your calculated efficiency is 30 MPG.
Efficiency guide
MPG Calculator Guide
MPG is simple math, but real-world mileage tracking gets more useful when you know what the number means, how it can be wrong, and how EVs and hybrids fit into the picture.
This guide explains how to calculate MPG, how MPGe works, and why a fuel log can give you a better long-term view than the number on your dashboard.
EV MPGe formula
MPGe compares electric energy to gasoline using 33.7 kWh as the energy equivalent of one gallon of gas.
That makes electric efficiency easier to compare against gas and hybrid vehicles.
Cost per mile
Cost per mile = total fuel or charging cost divided by miles driven.
This is often the clearest way to compare what different vehicles actually cost to drive.
Step by step
How to calculate MPG from fill-up data
1. Fill the tank
Start with a full tank and record the odometer reading, or let your mileage tracker keep the previous value.
2. Drive normally
Your next calculated MPG should reflect real-world use, so avoid changing your driving just for the measurement.
3. Fill the tank again
Record the new odometer reading and the amount of fuel added. Miles driven divided by gallons added gives the MPG for that cycle.
Why dashboard MPG may not match fill-up MPG
Your vehicle estimates fuel use from sensor data. That estimate can be useful, especially for trends, but it can differ from fill-up math because of short trips, cold starts, sensor assumptions, refueling variation, and optimistic dashboard calibration.
Fill-up tracking is not perfect either, but keeping records over time helps smooth out one-off noise and makes long-term efficiency changes easier to notice.
How SimpleFuel helps
SimpleFuel records mileage, fill-ups, charging sessions, MPG, MPGe, fuel cost, and maintenance history so your calculations become part of a vehicle timeline instead of a one-time math problem.
It supports gas, electric, hybrid, and plug-in hybrid vehicles, so the same app can track efficiency even as your garage changes.
