Gas Mileage Cost Calculator – Estimate Your Real Fuel Cost
Turn trip distance, fuel economy, and gas price into a cost per trip, month, and year.
How this calculator helps
Fuel spending is easy to underestimate because it is paid in small amounts spread across the month. This calculator converts a single trip, like a daily commute, into a clear monthly and yearly fuel budget, shows how that cost shifts as gas prices move, and can optionally compare the same trip against driving an EV.
Formula: Cost per trip = (trip distance ÷ MPG) × price per gallon. Monthly cost = cost per trip × trips per month. EV cost per trip = (trip distance ÷ EV efficiency in miles per kWh) × electricity rate.
Assumptions: This estimate uses a constant fuel economy and gas price. Real MPG varies with driving style, terrain, weather, and vehicle load, and gas prices change over time.
Worked example: A 30-mile round-trip commute at 28 MPG and $3.50 per gallon costs about $3.75 per trip. Driven 5 days a week, that is roughly $81 per month and about $977 per year.
- Trip distance: Total miles for the round trip or errand.
- Fuel economy: Your vehicle's average miles per gallon.
- Gas price: Current local price per gallon.
- Frequency: How often you make this trip, used to project monthly and yearly totals.
What the result means
The cost per trip shows what a single drive actually costs in fuel, which is often more revealing than a full tank price because it connects directly to a habit, like a commute or a school run. The monthly and yearly totals make it easier to see how a seemingly small trip adds up over time and how sensitive your budget is to gas price swings. The cost-per-100-miles figure strips out trip frequency entirely, so it is the fairest number to use when comparing two different vehicles or routes.
The gas price sensitivity table shows five nearby price points around what you entered, so you can see at a glance how much a $0.50 swing in gas prices would change your yearly fuel budget without re-running the calculator. If you enable the EV comparison, the tool applies your same trip distance and frequency to an electric vehicle's efficiency and local electricity rate, giving you a direct side-by-side estimate of what switching could save.
This calculator only estimates fuel, so it is best paired with the cost per mile calculator when you want a complete picture that includes insurance, maintenance, and depreciation. If you are deciding between two vehicles or comparing a longer commute against a shorter one, run each scenario separately and compare the monthly figures side by side.
Related calculators
EV charging cost calculator, Cost per mile calculator, and Car affordability help you evaluate the full cost of driving and buying a vehicle.
Frequently asked questions
- Does this include maintenance or insurance? No, this tool estimates fuel only. Use the cost per mile calculator for a full ownership cost.
- What if my MPG varies between city and highway driving? Use a blended average, such as the combined MPG figure listed on your vehicle's window sticker or owner's manual.
- Can I use this for a round trip? Yes, enter the full round-trip distance in the trip distance field.
- Should I update the gas price regularly? Yes, gas prices change often, so re-check the estimate whenever prices shift noticeably in your area.
- What does the price sensitivity table show? It recalculates your yearly cost at four other nearby gas prices, two lower and two higher than what you entered, so you can see your budget's exposure to price changes.
- How accurate is the EV comparison? It is a rough estimate that assumes a constant EV efficiency and electricity rate. Actual EV efficiency varies with weather, speed, and terrain, similar to gas mileage.
Creator & reviewers
Creator persona
- Morgan HayesVehicle costs & travel estimates
Reviewer personas
- Casey RowanUnits, conversions & measurement
- Devon ShawFormula & assumptions review