MPG Calculator

Calculate miles per gallon from the distance you drove and the fuel you used, with L/100 km, km per liter and the fuel cost per mile. Example: 300 miles on 10 gallons is 30 MPG, or 7.84 L/100 km.

How to use the MPG Calculator

1. Fill your tank and note the trip meter or odometer.
2. At the next fill-up, enter the miles driven and the gallons you added.
3. Add the fuel price if you want cost per mile.
4. Press Calculate to see MPG and metric equivalents.

Formula and method

MPG = miles driven / gallons of fuel used. To convert, L/100 km = 235.215 / MPG, and km per liter = MPG x 0.425144. Cost per mile = fuel price / MPG.

Worked example: 300 miles on 10 gallons

MPG to L/100 km chart

Ways to improve fuel economy

Keep tires at the recommended pressure, avoid hard acceleration and braking, remove roof racks and extra weight, reduce highway speed, and keep up with maintenance. These changes can improve gas mileage by several percent each.

Frequently asked questions

How do I calculate MPG?

Divide the miles you drove by the gallons of fuel you used. 300 miles on 10 gallons is 30 MPG.

How do I convert MPG to L/100 km?

Divide 235.215 by the MPG figure. 30 MPG is 7.84 L/100 km.

Is UK MPG different from US MPG?

Yes. An imperial gallon is about 20% larger, so the same car shows a higher MPG in the UK.

What is a good MPG?

Over 30 MPG combined is good for a gasoline car. Hybrids reach 45 to 55 and many EVs use the MPGe equivalent.

Why is my real MPG lower than the sticker?

Driving style, speed, weather, tires, cargo and short trips all lower real-world mileage.

How do I calculate cost per mile?

Divide the price per gallon by your MPG. At $3.50 and 30 MPG, fuel is about 12 cents a mile.

Sources

• U.S. Department of Energy: Fuel economy
• EPA: Fuel economy

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