Mr Deal's calculator
Gas prices by state this week, and what they cost you
Pick your state. You get this week's official average for regular and diesel, what a fill-up costs, and what your own driving costs per month at that price.
Every region and state the EIA publishes
Source: U.S. Energy Information Administration, weekly retail prices, all taxes included.
What this calculator adds to a price map
A price map tells you where the gallon is cheap. It does not tell you what gas costs you. Two numbers decide that, and neither is on the pump: how many miles you drive, and how many miles your car gets per gallon. The calculator multiplies them by your state's official weekly average, so the answer is a monthly amount you can put next to your rent or your grocery bill.
It also shows how far prices have moved in a year, because that is the part of your budget that changed without you doing anything differently. If you drive the typical 13,500 miles a year in a car that gets 25 mpg, every dollar added to the gallon costs you about $540 over twelve months.
Where the prices come from
Every Monday, the U.S. Energy Information Administration surveys retail gasoline outlets and publishes average prices for the country, its regions and nine states, taxes included. This page is rebuilt several times a day and always shows the latest release. When your state has no separate series, you see its regional average, and the calculator says so: it never pretends to know a local price it does not have.
Frequently asked questions
What are gas prices by state this week?
For the week of 09/21/26, the U.S. Energy Information Administration put the national average for regular gasoline at $4.478 a gallon. Among the nine states the EIA publishes separately, California was the most expensive at $6.003 and Texas the cheapest at $3.929. For other states, the calculator on this page shows the average of their EIA region.
How much does it cost to fill up a tank of gas?
Multiply your tank size by the price per gallon. At the national average of $4.478, a 15-gallon tank costs about $67.17, and a 20-gallon tank about $89.56. The calculator does it with your state's average and your own tank size.
Why are gas prices so high in September 2026?
AAA put the national average for regular at $4.43 a gallon on September 17, up 16 cents in a week and more than a dollar above a year earlier, with crude oil averaging around $100 a barrel amid volatility in the Strait of Hormuz. The Bureau of Labor Statistics measured gasoline prices up 27.4% over the twelve months to August 2026, against 3.4% for all consumer prices.
Why doesn't my state have its own price?
The EIA surveys retail stations every week and publishes separate averages for only nine states: California, Colorado, Florida, Massachusetts, Minnesota, New York, Ohio, Texas and Washington. Every other state is covered through its regional average, which is what this page shows, labelled as such. There is no free public feed of individual station prices in the United States.
How can I spend less on gas without changing cars?
Start with what costs nothing. Keeping tires at the recommended pressure improves gas mileage by about 0.6% on average and up to 3%, according to fueleconomy.gov, and each 1 psi drop in average pressure costs about 0.2%. Then look at how many miles you drive, because at current prices every avoided mile saves the full cost per mile shown by the calculator.
Keep going: what a car really costs per mile, whether an electric car pays off, and the complete guide to driving for less.