How much is the gas tax in Illinois?

Illinois charges a state motor-fuel tax of about 47 cents per gallon of gasoline, which is indexed to inflation and rises each July. On top of that, the federal excise tax adds 18.4 cents per gallon.

Why is Illinois gas tax so high?

Illinois doubled its motor-fuel tax in 2019 and tied it to inflation, so the rate climbs automatically every July 1. The revenue funds road, bridge, and transit infrastructure across the state.

Does Illinois charge sales tax on gasoline too?

Yes. Beyond the per-gallon motor-fuel tax, Illinois applies general sales tax to fuel and there can be local fuel taxes in Chicago and Cook County, making the true tax burden higher than the excise rate alone.

How do I calculate my annual gas tax?

Divide your yearly miles by your MPG to get gallons used, then multiply by the combined state and federal per-gallon rate. This tool does that math automatically when you choose annual mode.

Is the federal gas tax included in this estimate?

Yes. The calculator adds the federal 18.4-cent-per-gallon excise tax to the Illinois state motor-fuel rate so you see the full per-gallon tax baked into the pump price.

Illinois Gas Tax Calculator

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Every gallon of gasoline in Illinois carries a stack of taxes that buyers rarely see itemized at the pump. Illinois has one of the highest state motor-fuel taxes in the country, and it rises automatically each July. This calculator shows the tax in a single fill-up or across a full year of driving.

How it works

The fuel tax you pay is simply gallons burned multiplied by the combined per-gallon rate:

combined rate = Illinois motor-fuel tax + federal excise tax
gallons       = (annual mode) yearly miles ÷ MPG
              = (fill-up mode) gallons entered
fuel tax      = gallons × combined rate

Illinois’s state motor-fuel tax is about $0.47 per gallon and the federal excise is $0.184 per gallon, for a combined ~$0.654 per gallon before any local fuel or general sales tax. The tool uses these per-gallon excise figures; Chicago and Cook County add extra local fuel taxes not shown here.

Example

Driving 12,000 miles a year at 28 MPG burns about 429 gallons. At a combined $0.654 rate that is roughly $280 in fuel excise tax per year, before any local or general sales tax on the fuel.

Notes

The state rate is indexed to inflation and adjusts every July 1, so verify the current cents-per-gallon figure if you need exact numbers. Diesel is taxed at a higher state rate than gasoline in Illinois.