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Gas Mileage Calculator

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Find your vehicle's actual fuel efficiency (MPG) based on miles driven and gallons used - often more accurate for your real driving than the sticker rating.

Gas Mileage Calculator

Live
Fuel efficiency
28.0 mpg
For the most accurate result, fill the tank completely at both the start and end of your tracking period.

The formula

MPG = Miles driven / Gallons used
Example

350 miles on 12.5 gallons: 350 / 12.5 = 28.0 mpg.

Step-by-step guide

  1. Fill your tank completely and reset your trip odometer (or note the current mileage).
  2. Drive normally, then fill the tank completely again.
  3. Enter the miles driven and the gallons it took to refill, then read your actual MPG.

Common mistakes

Not filling the tank completely both times - a partial fill-up throws off the gallons-used figure and skews the result.
Judging fuel efficiency from a single tank with unusually heavy highway or city driving - averaging over several fill-ups gives a more representative number.

Frequently asked questions

Why is my actual MPG different from the sticker rating?

EPA ratings come from standardized test conditions. Real-world factors like driving style, traffic, weather, terrain, and vehicle load all affect your actual mileage, often lowering it somewhat below the rated figure.

How can I improve my gas mileage?

Smoother acceleration and braking, maintaining proper tire pressure, removing excess weight, and reducing highway speed are all commonly cited ways to improve real-world fuel efficiency.

Can I use this result in the Fuel Cost Calculator?

Yes - plug your calculated MPG into our Fuel Cost Calculator for a more accurate trip cost estimate than using the sticker rating.

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