Your gas budget at different prices
Prices move, so it helps to know what your budget looks like if they go up or down. This table uses your miles and MPG from the calculator.
| Price per gallon | Per month | Per year | Change per year |
|---|---|---|---|
| $3.00 | $129.50 | $1,554.05 | −$259.01 |
| $3.25 | $140.30 | $1,683.56 | −$129.50 |
| $3.50 (yours) | $151.09 | $1,813.06 | $0.00 |
| $3.75 | $161.88 | $1,942.57 | +$129.50 |
| $4.00 | $172.67 | $2,072.07 | +$259.01 |
Worked example: the EPA's typical car
- Fuel per year: 11,500 miles ÷ 22.2 MPG = about 518 gallons
- Cost per year: 518 gallons × $3.50 = about $1,813
- Per month: $1,813 ÷ 12 = about $151
- Per week: $1,813 ÷ 52 = about $35
The 11,500 miles and 22.2 MPG are the figures the EPA uses for a typical passenger vehicle. At those numbers the car puts out about 4.6 metric tons of CO2 a year, which matches the EPA's own estimate. Put in your own miles, MPG and price for your budget.
How the gas budget is calculated
Yearly fuel cost = miles per year ÷ MPG × price per gallon
Whatever period you enter is turned into miles a year first: monthly miles × 12, weekly miles × 52, or workday miles × workdays a week × 52. The calculator then works out gallons a year, the yearly cost, and divides back down to months (÷ 12) and weeks (÷ 52). Because a year isn't exactly 52 weeks, weekly figures are a close estimate.
Metric works the same way with kilometers, L/100 km and price per liter, using 1 mile = 1.609344 km and 1 US gallon = 3.785411784 liters. CO2 uses the EPA's 8,887 grams per gallon of gasoline.
Cedrick Reese built this budget tool for the question that matters after the road trip is over: what does driving cost every month? The default numbers come from the EPA's typical passenger vehicle (11,500 miles a year at 22.2 MPG) so the starting point is a real reference rather than a guess, and the result checks out against the EPA's own 4.6-ton CO2 figure for that car. The price table is computed from your price, never from published averages, and the car picker's ratings are rebuilt from the fueleconomy.gov dataset whenever it updates.
Gas budget questions
How much does gas cost per month?
Divide the miles you drive in a year by your MPG to get the gallons you'll use, multiply by the price per gallon, then divide by 12. For 11,500 miles a year at 22.2 MPG and an example price of $3.50, that's about $151 a month.
How many miles does a typical car drive in a year?
The EPA bases its typical passenger vehicle on about 11,500 miles a year. Your own number can be very different, so check your odometer readings a year apart, or add up a normal week and multiply by 52.
How do I work out how many miles I drive a week?
Write down your odometer reading, drive a normal week, and read it again. The difference is your weekly miles. Do it for two or three weeks and average them if your driving changes a lot.
How much does a 25-cent rise in gas prices cost me?
Divide your yearly miles by your MPG to get gallons per year, then multiply by $0.25. At 11,500 miles and 22.2 MPG you burn about 518 gallons a year, so a 25-cent rise adds about $130 a year, or about $11 a month.
Should I budget with my real MPG or the EPA rating?
Use your real MPG if you know it. Track a few fill-ups by dividing the miles driven by the gallons it takes to refill. The EPA combined rating is a reasonable starting point if you don't have your own number yet.
Source for the typical vehicle figures: EPA, Greenhouse Gas Emissions from a Typical Passenger Vehicle.
More fuel tools
Planning a single drive instead? The fuel cost calculator handles one trip, and the trip cost calculator adds tolls, lodging and a per-person split.
If your budget is mostly a car swap decision, compare fuel costs between two vehicles on our sister site, GasMileageCalculators.com.
To shrink the yearly number, see how to save money on gas, or check whether premium gas is adding to it.
Sources
Last reviewed: October 4, 2026.