Gas Mileage Calculator
Miles per gallon, cost per mile, and trip fuel cost
Fuel Economy
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This gas mileage calculator finds your vehicle's fuel economy in MPG from the miles driven and gallons used. Add the fuel price to also see your cost per mile and the total fuel cost of the trip, plus metric km/L and L/100km.
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Frequently Asked Questions
How do I calculate gas mileage (MPG)?
Divide the miles you drove by the gallons of fuel used. Fill your tank, note the odometer, drive until you refuel, then divide the miles driven by the gallons it took to fill up again. Miles ÷ gallons = MPG.
What is good gas mileage?
For gas cars, 25–30 MPG is average, 30–40 MPG is good, and 40+ MPG is excellent (usually hybrids). Trucks and SUVs often get 15–22 MPG. Highway MPG is typically higher than city MPG.
How do I convert MPG to L/100km?
Divide 235.215 by the MPG value. For example, 30 MPG equals 235.215 ÷ 30 = 7.84 L/100km. Lower L/100km means better efficiency, which is the opposite of MPG.
What lowers my gas mileage?
Aggressive driving, speeding, excess idling, under-inflated tires, roof racks, extra cargo weight, and cold weather all reduce MPG. Gentle acceleration and steady highway speeds around 55–60 mph maximize efficiency.
How much does a trip cost in gas?
Divide the trip distance by your MPG to get gallons needed, then multiply by the fuel price. A 300-mile trip at 30 MPG uses 10 gallons; at $3.50/gallon that is $35.