Fuel Economy Calculators

Calculate gas mileage (MPG), estimate fuel costs for any trip, compare annual fuel expenses between vehicles, find your true cost per mile, convert between MPG and L/100km, size fuel injectors, and project savings from improving your fuel efficiency. All with instant results and metric equivalents.

All Fuel Economy Calculators

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Gas Mileage Calculator

Calculate your vehicle's gas mileage (MPG) from distance traveled and fuel used. See cost per mile and metric equivalents.

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Fuel Cost Calculator

Calculate the fuel cost for any trip distance based on your vehicle's MPG and current gas price. Compare regular, mid-grade, and premium.

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Fuel Savings Calculator

Compare annual fuel costs between two vehicles. See how much you'd save by switching to a more fuel-efficient car.

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Cost Per Mile Calculator

Calculate the true all-in cost per mile including fuel, insurance, maintenance, depreciation, and financing.

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Fuel Injector Flow Rate Calculator

Calculate required fuel injector flow rate (lb/hr or cc/min) based on target horsepower, BSFC, number of injectors, and duty cycle.

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Fuel Tank Range Calculator

Calculate how far you can drive on a full tank or remaining fuel based on your vehicle's MPG and tank size.

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Annual Fuel Cost Calculator

Calculate your total annual fuel expenditure based on yearly miles driven, vehicle MPG, and local fuel price.

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MPG Improvement Savings Calculator

Calculate how much money you save by improving your vehicle's fuel economy from one MPG to another over a year.

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MPG to L/100km Converter

Convert between MPG (US), MPG (Imperial), km/L, and L/100km. Bidirectional fuel economy unit conversion with instant results.

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💡 Understanding Fuel Economy

Fuel economy measures how far a vehicle can travel per unit of fuel. In the US, it's expressed as miles per gallon (MPG) — higher is better. In most of the world, it's expressed as liters per 100 kilometers (L/100km) — lower is better. These are inverse measures: 25 MPG = 9.4 L/100km.

Your actual fuel economy depends on driving habits, terrain, weather, tire pressure, vehicle maintenance, and load. EPA-rated MPG is a standardized test result — real-world fuel economy is typically 10–20% lower. City driving burns 20–30% more fuel than highway due to frequent acceleration and idling. Properly inflated tires alone can improve MPG by 3%.

The average American drives 13,500 miles/year spending $1,700–$2,500 on fuel. Use the Fuel Savings Calculator to see how much switching to a more efficient vehicle could save you.