The Illinois gas tax on gasoline is 48.3 cents per gallon through June 30, 2026, and rises to 49.6 cents per gallon on July 1, 2026. That is only the state motor fuel tax. Once you add federal excise tax, a prepaid state sales tax, small environmental fees, and county or city fuel taxes where they apply, the total tax on a gallon of regular gas in much of Illinois runs between 84 and 91 cents before you pay for a drop of fuel.
Current State Rates on Gasoline and Diesel
The Illinois Motor Fuel Tax is an excise tax charged on every gallon of fuel used on public highways and on recreational watercraft. Distributors pay it first and pass the cost through to the pump.
Through June 30, 2026, the statewide rates are 48.3 cents per gallon on gasoline and gasohol, and 55.8 cents per gallon on diesel. Starting July 1, 2026, those rates rise to 49.6 cents on gasoline and gasohol, and 57.1 cents on diesel.1Illinois Department of Revenue. Motor Fuel Tax Rates and Fees2Illinois Department of Revenue. FY 2026-23, Change in the Motor Fuel Tax Rate, Effective July 1, 2026, Through June 30, 2027
Diesel sits higher because the statute adds 7.5 cents per gallon on top of the gasoline rate for diesel, liquefied natural gas, and propane.3Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 505 – Motor Fuel Tax Law
Why the Rate Goes Up Every July
For nearly thirty years, the Illinois motor fuel tax sat frozen at 19 cents per gallon. The 2019 Rebuild Illinois capital plan doubled the rate to 38 cents overnight and tied every future increase to inflation. Since then, the tax has adjusted upward automatically on July 1 each year, with no vote required from the General Assembly.
The Department of Revenue calculates the adjustment by comparing the average Consumer Price Index for All Urban Consumers over the 12 months ending in March against the same period a year earlier. Whatever percentage increase that produces gets applied to the current rate, rounded to the nearest tenth of a cent.3Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 505 – Motor Fuel Tax Law There is no cap on how large the yearly bump can be. The rate cannot fall either, because the statute only adjusts for a “percentage increase, if any.”
Rate History Since 2019
The gasoline rate since the 2019 overhaul:
- Before July 2019: 19.0 cents (held since 1990)
- July 2019: 38.0 cents
- July 2020: 38.7 cents
- July 2021: 39.2 cents
- January 2023: 42.3 cents (mid-year catch-up)
- July 2023: 45.4 cents
- July 2024: 47.0 cents
- July 2025: 48.3 cents
- July 2026: 49.6 cents
The steepest jumps came in 2022 and 2023 when inflation ran hot. The gap between July 2021 and January 2023 reflects a temporary suspension of the scheduled increase that the legislature later let expire.1Illinois Department of Revenue. Motor Fuel Tax Rates and Fees
Everything Else Stacked on a Gallon
The state motor fuel tax is one layer. Several other charges sit on top of it, and they are what push the real per-gallon total well past the headline rate.
Federal Excise Tax
The federal government charges 18.3 cents per gallon on gasoline and 24.3 cents on diesel, plus a 0.1-cent-per-gallon Leaking Underground Storage Tank surcharge on both. That works out to 18.4 cents total on gasoline and 24.4 cents on diesel. Those rates have been fixed since 1993 and are not indexed to inflation.4Office of the Law Revision Counsel. 26 U.S. Code 4081 – Imposition of Tax
Illinois Prepaid Sales Tax
Illinois’s 6.25% state sales tax also applies to motor fuel, but retailers prepay it as a flat cents-per-gallon amount when they buy fuel from distributors. The Department of Revenue recalculates the figure every six months from average selling prices. For the first half of 2026, the prepaid rate is 17 cents per gallon on most gasoline blends and 15 cents on gasohol (E15).5Illinois Department of Revenue. Prepaid Sales Tax Rates Because it tracks fuel prices, this rate rises and falls over time.
Environmental Fees
Two smaller charges apply to every gallon sold in Illinois: an environmental impact fee of 0.8 cents per gallon and an underground storage tank tax of 0.3 cents per gallon.1Illinois Department of Revenue. Motor Fuel Tax Rates and Fees
County and Municipal Fuel Taxes
Several Illinois counties add their own per-gallon fuel taxes. DuPage, Kane, Lake, McHenry, and Will counties each levy a county motor fuel tax that adjusts annually on July 1 using the same CPI mechanism as the state rate.6Illinois Department of Revenue. County Motor Fuel Tax Cook County separately imposes a 6-cent-per-gallon tax, and Chicago layers its own municipal fuel tax on top of that. Filling up in the city costs measurably more than filling up downstate for this reason.
What a Gallon Actually Costs in Tax
For a driver buying regular gasoline in Cook County during the first half of 2026, the per-gallon tax breakdown looks like this:
- State motor fuel tax: 48.3 cents
- Federal excise tax: 18.4 cents
- Prepaid sales tax: 17.0 cents
- Cook County fuel tax: 6.0 cents
- Environmental impact fee: 0.8 cents
- Underground storage tank tax: 0.3 cents
That comes to roughly 90.8 cents per gallon before any Chicago municipal tax. Downstate drivers in counties without a local fuel tax still pay around 84 cents per gallon in combined taxes. After the July 2026 state increase, each of those totals climbs another 1.3 cents.
What Electric Vehicle Owners Pay Instead
Drivers of battery-electric vehicles buy no gasoline, so they contribute nothing through the motor fuel tax. Illinois closes that gap with a supplemental annual charge on EV registrations that flows into the Road Fund alongside fuel tax revenue.7Illinois Secretary of State. Electric Vehicle License Plates As of 2026, the total annual renewal for an electric vehicle is $251, combining the standard registration fee and the EV surcharge. If you’re weighing the switch to an EV, that fee offsets part of the fuel-tax savings.
Where the Money Goes
The Illinois Constitution locks all revenue from fuel taxes and vehicle fees into transportation. None of it can be diverted to the general fund or spent on anything unrelated to roads, bridges, transit, or transportation administration. That protection was added by constitutional amendment in 2016.
Roughly 45.6% of state motor fuel tax revenue stays with the state, split between the Road Fund for routine highway maintenance and Illinois Department of Transportation operations, and the State Construction Account Fund for larger capital projects. The remaining 54.4% is distributed to local governments through a fixed statutory formula: 49.10% to municipalities, 16.74% to Cook County, 18.27% to all other counties combined, and 15.89% to road districts. Local governments must spend the money on road and bridge construction, reconstruction, and maintenance.8Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 505/8