How to Calculate MPG Formulas

Higher mpg translates into lower costs for pumping gasoline.

The acronym mpg stands for "miles per gallon," the non-metric measurement of fuel economy in cars and trucks. The mpg formula allows you to compare the fuel efficiency among vehicles. If you're not satisfied with your car's mileage, you might consider trading it in on a more fuel-efficient vehicle. The better gas mileage your car or truck gets, the less time and money you will be spending at the pump.

Instructions

1. Fill your gas tank until the pump clicks off.

2. Write down the number of miles on your odometer before you begin driving again, or reset your tripmeter to zero.

3. Follow your normal driving patterns on city roads and highways until you think it is time to fuel up again. Miles per gallon can be calculated after using a small amount of gasoline, but the mpg result could reflect abnormalities in your driving routine.

4. Fill your gas tank again until the pump clicks off. For the most accurate result, use the same station and pump, to avoid the possibility of slight mechanical differences at another pump.

5. Note the number of miles driven since your last fill-up. Subtract the number you wrote down at the first fill-up from your present odometer reading to calculate the miles you drove, or note the number on the tripmeter.

6. Divide your driving distance by the number of gallons of fuel you just pumped. This is the formula for mpg (number of miles / gallons of fuel). For instance, if you drove 300 miles and you used 10 gallons of gas, divide 300 by 10 to get 30 mpg.

Tips & Warnings

• Your mpg result will be more precise if you calculate the formula using the exact reading of gallons pumped and miles driven with no rounding.

References

• Ecomodder: How to Calculate MPG / Fuel Economy Formula
• Hypermile Me: How to Calculate Your Gas Mileage