Gas prices in Illinois
Regular gas costs an average of $4.29 a gallon in Illinois, and diesel $6.53, based on the Midwest regional figure for the week of September 28, 2026. That's 18 cents below the national average.
EIA doesn't publish a separate average for Illinois, so this is the Midwest average, which covers Illinois. Prices at individual stations vary.
| Fuel | Illinois | U.S. average |
|---|---|---|
| Regular | $4.29 | $4.47 |
| Diesel | $6.53 | $6.38 |
What gas costs in Illinois
Filling a 15-gallon tank with regular costs about $64.35. A 300-mile road trip in a car that gets 25 mpg uses 12 gallons, which comes to about $51.48.
Frequently asked questions
How much is gas in Illinois right now?
Regular gas averages $4.29 a gallon based on the Midwest regional figure for the week of September 28, 2026.
How much is diesel in Illinois?
Diesel averages $6.53 a gallon based on the Midwest figure.
How much does it cost to fill up in Illinois?
A 15-gallon tank of regular costs about $64.35 at the average price.
Where do these prices come from?
The U.S. Energy Information Administration surveys retail gas stations every week and publishes averages for the nation, regions and nine states every Monday.
Gas prices in Midwest over time
Since 6 October 2025, the typical price of regular gas has risen by 136 cents.
Weekly averages from the U.S. Energy Information Administration. See national price history.
Gas prices in other states
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- District of Columbia
- Florida
- Georgia
- Hawaii
- Idaho
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming