Gas Mileage Calculator
What Is Gas Mileage (MPG) and Why It Matters
Gas mileage, or miles per gallon (MPG), tells you how far your vehicle travels on one gallon of fuel. It’s the single biggest factor in your fuel costs – a car averaging 20 MPG costs roughly twice as much to fuel as one averaging 40 MPG over the same distance, even at identical gas prices.
Gas Mileage Formula
MPG = Miles Driven ÷ Gallons of Fuel Used
Example: if you drove 300 miles and used 10 gallons of gas, your fuel economy is 300 ÷ 10 = 30 MPG.
Trip Cost Formula
Trip Cost = (Distance ÷ MPG) × Price per Gallon
Example: a 300-mile trip at 30 MPG with gas at $3.50/gallon costs (300 ÷ 30) × $3.50 = $35.00 in fuel.
Frequently Asked Questions
What is considered good gas mileage?
30-40 MPG is considered good for a regular gasoline car, 40+ MPG is excellent (typical of hybrids), 20-30 MPG is average, and below 20 MPG is considered poor fuel economy.
How do I calculate my car’s MPG manually?
Fill your tank completely and note the odometer reading. Drive normally, then fill up again and record the miles driven and gallons needed to refill. Divide miles driven by gallons used to get your MPG.
How can I improve my gas mileage?
Maintain steady highway speeds (55-65 mph is typically most efficient), keep tires properly inflated, remove unnecessary weight from the vehicle, stay current on maintenance like oil changes and air filters, and use cruise control on highways.
Does this calculator work for both US (MPG) and metric (L/100km) units?
Yes, the calculator includes metric conversions alongside the MPG result, so you can compare fuel economy whether you think in miles/gallons or liters/100km.