The price on the gas station sign is per gallon, but what you actually feel is the total at the pump. Turning one into the other, and into a monthly fuel budget, is simple once you know your tank size and how far you drive.
The short version
- Fill-up cost = gallons × price per gallon.
- At the U.S. average of $4.35 (week of October 5, 2026, EIA), a 15-gallon fill-up is $65.25.
- The same fill-up was $58.05 in Texas and $93.45 in California.
- Monthly fuel cost = miles ÷ miles per gallon × price.
Find your tank size
Your owner’s manual lists the fuel tank capacity, and many cars show it on the gas cap or in the specs online. Many compact cars hold roughly 12 to 14 gallons and many full-size trucks and SUVs 20 or more, but check your own car. You rarely fill a tank from empty, so you can also just note how many gallons your last fill-up took.
What a fill-up costs by state
| Where | Price per gallon | 12 gallons | 15 gallons | 20 gallons |
|---|---|---|---|---|
| Texas | $3.87 | $46.44 | $58.05 | $77.40 |
| Florida | $3.97 | $47.64 | $59.55 | $79.40 |
| U.S. average | $4.35 | $52.20 | $65.25 | $87.00 |
| New York | $4.38 | $52.56 | $65.70 | $87.60 |
| Washington | $5.42 | $65.04 | $81.30 | $108.40 |
| California | $6.23 | $74.76 | $93.45 | $124.60 |
Prices change weekly. Check today’s average for your state or city on our gas prices page before you budget.
Your monthly and yearly fuel cost
Divide the miles you drive by your car’s miles per gallon (mpg) to get gallons, then multiply by the price.
| Miles per month | 25 mpg at $4.35 | 35 mpg at $4.35 |
|---|---|---|
| 500 | $87.00 | $62.14 |
| 1,000 | $174.00 | $124.29 |
| 1,500 | $261.00 | $186.43 |
Over a year at 12,000 miles and 25 mpg, that is 480 gallons, or about $2,088 at $4.35. Every 10-cent change in the price moves the yearly total by $48.
Example
Brianna commutes 32 miles a day, five days a week, near Orlando in a car that gets 30 mpg. That’s about 693 miles a month (32 × 5 × 52 ÷ 12), or 23.1 gallons. At Florida’s $3.97, she spends about $91.75 a month on the commute. A coworker driving the same route in a 20-mpg SUV spends about $137.63.
Cost per mile
Price ÷ mpg gives you the fuel cost of one mile. At $4.35 and 25 mpg, each mile costs about 17.4¢. That makes it easy to price a trip: a 300-mile drive costs about $52 in fuel.
Ways to spend less at the pump
- Compare stations on your route with a price app. A 20-cent difference on 15 gallons is $3.
- Ask whether the station charges less for cash or debit.
- Keep tires at the pressure on the door sticker and avoid hard acceleration.
- Use the grade your owner’s manual recommends. If it says regular, premium doesn’t help.
- Combine errands into one trip.
See gas prices across the U.S. for where gas is cheapest, and add fuel to your plan with our monthly budget calculator.
Road trip fuel cost
For a trip, divide the distance by your car’s highway mpg and multiply by the price where you will fill up. Prices can vary a lot along the way.
Example
Houston to Dallas is roughly 240 miles each way. In a car that gets 32 mpg on the highway, the round trip uses about 15 gallons (480 ÷ 32). At Texas’s $3.87, that is about $58. The same 480 miles of driving in California, at $6.23, would cost about $93.
Does a fuller or emptier tank save money?
The price per gallon is the same whether you buy 5 gallons or 15, so the total cost of driving doesn’t change with how full you fill up. What changes is how often you stop. Filling up when prices dip, or before entering a higher-priced area, is what saves money.
Regular vs. premium
Premium gasoline usually costs noticeably more per gallon than regular. If your owner’s manual says regular is fine, paying for premium doesn’t make the car more efficient. If it requires premium, use it. On a 15-gallon fill-up, every 50 cents per gallon is $7.50.
Hybrids and EVs
A hybrid that gets 50 mpg uses half the gas of a 25-mpg car for the same miles: 1,000 miles a month would be 20 gallons, about $87 at $4.35 instead of $174. For an electric car, the “fill-up” is electricity: miles ÷ miles per kWh × your price per kWh. Our electricity price pages show the average price in each state.
