Gas Cost Calculator 2025
Calculate your exact monthly and annual fuel expenses, cost per mile, gallons consumed, and CO2 emissions. Supports simple and advanced driving profiles — with state-specific gas prices.
How Gas Costs Add Up in 2025
Gasoline is one of the biggest variable costs of car ownership in the United States. Understanding how much you spend on fuel helps you budget, evaluate vehicle efficiency, and decide whether switching to an EV or hybrid makes financial sense.
How Fuel Costs Are Calculated
Your fuel cost is determined by three factors: miles driven (how much you drive), fuel efficiency (your vehicle's MPG), and gas price (what you pay per gallon). The formula is simple: (Miles ÷ MPG) × Price per Gallon = Total Fuel Cost. City driving typically uses 15–30% more fuel than highway driving at steady speeds.
Gas Taxes by State (2025)
Every gallon of gas includes a federal excise tax of 18.4¢ per gallon plus state taxes that vary widely. California has the highest combined gas tax (about 68¢/gal), while Alaska has the lowest (about 9¢/gal). The average combined state+federal gas tax in the US is approximately 49¢ per gallon. These taxes fund highway construction and maintenance.
Gas vs. Electric Vehicle Cost Comparison
The average EV gets about 3–4 miles per kWh and the average US residential electricity rate is about 13.5¢ per kWh in 2025. That means an EV costs roughly 3.4–4.5¢ per mile in fuel, compared to 10–20¢ per mile for a gas car. The average driver saves $800–$1,500 per year on fuel alone by switching to electric.
Fuel Economy Trends
The average fuel economy of new US vehicles has risen from about 20 MPG in 2005 to 26 MPG in 2025. Hybrids average 40–50 MPG, plug-in hybrids 60–100 MPGe, and full EVs 100–130 MPGe. The EPA's 2025 emissions standards are pushing automakers toward even more efficient vehicles, with many new SUVs now achieving 30+ MPG highway.
Frequently Asked Questions
Divide your monthly miles by your vehicle's MPG to get gallons used, then multiply by the gas price per gallon. Example: 1,200 miles ÷ 25 MPG = 48 gallons × $3.50 = $168 per month.
The average US regular gas price in 2025 is about $3.40–$3.70 per gallon. California averages $4.50–$5.50, while Texas and Gulf states average $2.80–$3.20. Hawaii and Washington also tend to be above $4.50. Prices fluctuate seasonally — typically higher in summer and lower in winter.
Fuel-only cost per mile at $3.50/gal: 30 MPG car = 11.7¢/mi, 25 MPG SUV = 14¢/mi, 15 MPG truck = 23.3¢/mi. The IRS 2025 standard mileage rate is 70¢/mi for total cost (fuel + maintenance + insurance + depreciation).
The average US driver consumes about 500–600 gallons of gasoline per year, driving roughly 13,500–14,500 miles annually in a vehicle averaging 25–28 MPG. At 2025 prices, that's about $1,800–$2,200 per year in fuel costs.
One gallon of gasoline produces 19.6 pounds (8,887 grams) of CO2. A car driving 13,500 miles/year at 25 MPG produces about 5.3 tons of CO2 annually. EVs produce zero tailpipe emissions, though grid electricity generation may still produce emissions (about 2–3 tons/year equivalent on the average US grid).
Yes, EVs are significantly cheaper on fuel. At the US average electricity rate of 13.5¢/kWh with an EV getting 3 mi/kWh, the cost is about 4.5¢/mile vs. 14¢/mile for a 25 MPG gas car at $3.50/gal. The average driver saves $800–$1,500 per year on fuel. However, EVs typically cost more upfront ($5,000–$15,000 more), though federal tax credits of up to $7,500 narrow the gap.