Gas Mileage Calculator

Calculate your gas mileage (MPG) and fuel cost in one place. Enter your odometer start and end readings, gallons of gas used, and gas price per gallon to get your miles per gallon, total fuel cost, and cost per mile. Supports both US (miles/gallons) and metric (km/liters) units.

Record your odometer reading when you fill up the tank.

Record your odometer reading at the next fill-up.

Enter the amount of fuel you added at the second fill-up.

Price per gallon or per liter depending on your selected unit.

Results

Fuel Efficiency

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Total Fuel Cost

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Cost per Mile / km

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Distance Traveled

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Fuel Cost Breakdown

Frequently Asked Questions

How do I calculate gas mileage (MPG)?

To calculate gas mileage, record your odometer reading when you fill up, then note the reading again at your next fill-up. Subtract the first reading from the second to get the distance traveled, then divide that distance by the number of gallons added at the second fill-up. The result is your miles per gallon (MPG).

What is a good MPG for a car?

A good MPG varies by vehicle type. For passenger cars, 30 MPG or above is generally considered good fuel efficiency. Hybrids often achieve 45–60 MPG, while SUVs and trucks typically range from 15–25 MPG. You can compare vehicles at fueleconomy.gov for a full breakdown.

How can I improve my gas mileage?

You can improve gas mileage by maintaining proper tire inflation, avoiding aggressive acceleration and hard braking, reducing highway speeds, keeping up with regular engine maintenance, and removing excess weight from your vehicle. Carpooling, combining errands, and using cruise control on highways also help.

Does 4-wheel drive use more fuel?

Yes, 4-wheel drive (4WD) vehicles are generally less fuel-efficient than front-wheel drive (FWD) or rear-wheel drive (RWD) vehicles. Powering all four wheels requires more engine effort, which increases fuel consumption, especially at higher speeds.

How do I convert MPG to liters per 100 km (L/100km)?

To convert US MPG to L/100km, divide 235.21 by your MPG value. For example, 30 MPG equals approximately 7.84 L/100km. Conversely, divide 235.21 by your L/100km figure to get MPG.

Why does my fuel efficiency vary between fill-ups?

Fuel efficiency can vary due to driving conditions (city vs. highway), weather, air conditioning use, tire pressure, fuel quality, traffic, and driving habits. For the most accurate average MPG, track several fill-ups over time rather than relying on a single measurement.

How much does the average American spend on gas per year?

According to the American Automobile Association (AAA), the average American driver spends approximately $3,000 per year on gasoline. This varies widely based on vehicle fuel efficiency, annual mileage, and local gas prices.

Does tire pressure affect gas mileage?

Yes, under-inflated tires increase rolling resistance, which forces your engine to work harder and burns more fuel. Keeping your tires inflated to the manufacturer's recommended pressure can improve fuel efficiency by up to 3%. Check your tire pressure monthly, especially during temperature changes.

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