Gas Prices in Illinois
Gas prices in Illinois depend a lot on where you fill up. The EIA doesn’t publish a statewide Illinois average, but in the week of Oct. 12, 2026, the Midwest region averaged $4.15 for regular while the Chicago average was $4.70, about 55 cents higher. Both went up that week, about 4 and 6 cents, while the national average edged down. Below I break down the taxes behind the Chicago premium, how Illinois compares with its neighbors, and where to fill up for less.
Prices: EIA weekly data, updated automatically · By Nathan Brooks · Reviewed Oct. 15, 2026
Regular and diesel: EIA Midwest average for the week of Sept. 21, 2026. The EIA doesn’t publish a separate weekly average for Illinois, so we show the Midwest regional average, which Illinois is part of.
What drives gas prices in Illinois
- A high, indexed gas tax. Illinois normally raises its motor fuel tax every July 1 for inflation. A 2026 law suspended the July 1, 2026 increase for six months, through Dec. 31, 2026, according to the Illinois Department of Revenue. If you’re budgeting for next year, keep an eye on what happens after that date.
- Sales tax on gas. Illinois also applies sales tax to gasoline, on top of the per-gallon tax. Because it’s a percentage, it takes a bigger bite when prices are high, as they are this year.
- Chicago and Cook County taxes. The city and county add their own per-gallon taxes. That’s a big part of why Chicago prices are often among the highest in the Midwest.
- Summer blend in the Chicago area. The Chicago region uses a special cleaner-burning summer gasoline that costs more to make, which widens the gap with downstate in the warm months.
Illinois vs. neighboring states
| State | Regular (this week) | State gas tax | Tax vs. Illinois |
|---|---|---|---|
| Illinois | $4.39 | 70.4¢ | — |
| Indiana | $4.39 | 63.1¢ | −7.3¢ |
| Wisconsin | $4.39 | 32.9¢ | −37.5¢ |
| Missouri | $4.39 | 30.0¢ | −40.4¢ |
| Iowa | $4.39 | 30.0¢ | −40.4¢ |
| Kentucky | $4.39 | 26.4¢ | −44.0¢ |
Prices: EIA weekly averages. States without their own EIA average show their region’s average (Indiana, Wisconsin, Missouri, Iowa and Kentucky use the Midwest average), so real border differences can be bigger or smaller. Taxes: Tax Foundation, July 1, 2026 (state taxes and fees, excluding the 18.4¢ federal tax).
Prices moved against the trend this week
Illinois went against the national trend in the week of Oct. 12: prices rose in the Midwest and in Chicago while most of the country got a little cheaper. One week isn’t a trend, but it’s a reminder that Midwest prices can move on their own. Compared with a year ago, Chicago drivers are paying about $1.45 a gallon more.
The single best move in Illinois is geographic. If you commute from the suburbs into Chicago, fill up before you enter Cook County. If you live near Missouri, Iowa, Wisconsin or Kentucky, the lower taxes across the line can make a real difference. Then stack a grocery fuel program on top if you already shop at Jewel-Osco, Mariano’s or Meijer. — Nathan Brooks
What to watch next
Jan. 1, 2027. The suspension of this year’s motor fuel tax increase runs through Dec. 31, 2026. Check the Illinois Department of Revenue for the rate that applies after that.
Best ways to save on gas in Illinois
- Fill up outside Cook County. Collar-county and downstate stations are often noticeably cheaper than those in Chicago. If you commute in, this costs you nothing but timing.
- Near a state line? Missouri, Iowa, Wisconsin and Kentucky all have much lower state gas taxes than Illinois, so stations just across the border are often cheaper. Compare states.
- Jewel-Osco “for U” rewards turn grocery points into cents off per gallon at participating stations. Check the app before you fill up.
- Mariano’s and other Kroger-family stores earn Kroger fuel points (100 points = 10¢ off per gallon). How Kroger points work.
- Meijer runs fuel promotions for mPerks members from time to time, and Costco and Sam’s Club are spread across the Chicago suburbs.
Programs and terms are set by each company and can change. Check the official site or app before you sign up.
Propane in Illinois
Home propane is one area where Illinois does well. The state opened the EIA’s heating season survey at $1.83 a gallon (Oct. 5, 2026), about 77 cents below the U.S. average of $2.60 and among the lowest prices in the country. Like its farm-state neighbors, Illinois uses a lot of propane and sits near major supply. Low prices are a good reason to fill up early, but cold winters still mean big bills, so ask your supplier about pre-buy or budget plans. Compare states on our propane prices by state table.
- Grill and RV tanks: where to refill propane and exchange vs. refill.
- Home tanks: tank sizes and how long a tank lasts, and a fill-up cost calculator.
- Help with heating bills: Illinois LIHEAP (state profile) can help eligible households pay for heating fuel, including propane.
Quick answers
Why is gas so expensive in Chicago?
Chicago drivers pay the Illinois state tax plus sales tax, Cook County and City of Chicago gas taxes, and a special cleaner-burning summer blend.
Did the Illinois gas tax go up in July 2026?
No. A 2026 law suspended the July 1, 2026 inflation increase for six months, through Dec. 31, 2026, according to the Illinois Department of Revenue.
Is propane cheap in Illinois?
Illinois has some of the lowest home propane prices in the country. In the EIA’s first weekly survey of the 2026-27 heating season (Oct. 5, 2026), Illinois averaged $1.83 a gallon, compared with $2.60 for the U.S.
Keep saving
Sources
EIA Gasoline and Diesel Fuel Update · Tax Foundation: state gas tax rates (July 1, 2026) · EIA weekly residential propane prices · Illinois Department of Revenue: motor fuel tax rate (FY 2026-23) · Illinois Department of Revenue: motor fuel tax rates · Illinois LIHEAP (state profile)
FuelPriceScout is an independent information site. We don’t sell fuel and we’re not affiliated with any gas station, retailer or rewards program mentioned here. Prices are averages from public sources and are not what a specific station charges; program terms can change, so always check the official site before you sign up. How we get our data.