Fuel Cost & Savings Calculator
Calculate your annual fuel cost based on miles driven, MPG, and gas price. Use this to budget driving expenses or compare fuel costs between two vehicles before buying.
About this calculator
Your annual fuel cost depends on three factors: how far you drive, how efficiently your vehicle burns fuel, and what you pay per gallon. The core formula is: Annual Cost = (Miles Per Year ÷ MPG) × Fuel Price. This tells you how many gallons you consume per year, then multiplies by the price per gallon. A fuel type multiplier can adjust the result for premium, diesel, or E85 fuels, which differ in energy content and price. Improving your MPG even slightly has a large compounding effect on yearly spend — for example, going from 20 to 25 MPG on 15,000 miles saves 150 gallons annually. This calculator is especially useful when comparing a gas-sipping hybrid to a larger SUV.
How to use
Suppose you drive 12,000 miles per year in a car that gets 28 MPG, and gas costs $3.50 per gallon. Step 1: Divide miles by MPG → 12,000 ÷ 28 = 428.6 gallons per year. Step 2: Multiply by fuel price → 428.6 × $3.50 = $1,500 per year. If you consider a vehicle with 35 MPG instead: 12,000 ÷ 35 × $3.50 = $1,200 per year — a $300 annual saving. Over five years that's $1,500 in your pocket just from better fuel economy.
Frequently asked questions
How do I calculate my annual fuel cost from MPG and gas price?
Divide your annual mileage by your vehicle's MPG to get total gallons consumed per year, then multiply by the price per gallon. For example, 15,000 miles ÷ 25 MPG = 600 gallons × $3.40 = $2,040 per year. This simple formula makes it easy to budget for fuel or compare vehicles side by side.
How much money can I save by switching to a more fuel-efficient car?
The savings depend on the MPG difference, miles driven, and fuel price. Going from 20 MPG to 30 MPG on 15,000 miles at $3.50/gallon saves 250 gallons, or $875 per year. Over a five-year ownership period that adds up to $4,375 — often enough to offset a significant portion of a higher purchase price for a more efficient vehicle.
Why does fuel type affect my annual fuel cost calculation?
Different fuel types — regular, premium, diesel, and E85 — have different pump prices and energy densities, which affect your real-world cost per mile. Diesel, for example, often costs more per gallon but delivers better MPG, so the net cost can be lower. E85 ethanol is cheaper per gallon in many regions but reduces fuel economy by roughly 25%, so the savings may not be as large as the sticker price suggests.