Fuel Economy Formula

Fuel economy is simply how far you go on a unit of fuel.

MPG = Distance ÷ Fuel Used

Where

Distance Miles driven
Fuel used Gallons consumed

Worked example

Driving 300 miles on 12 gallons gives 300 ÷ 12 = 25 MPG.

Metric conversion: L/100km = 235.215 ÷ MPG. Unlike MPG, a lower L/100km is better.

Use the Fuel Economy Calculator for all units at once.

Scroll to Top

The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.