Estimate your Illinois property tax based on the state's 2.08% average effective rate — the second highest in the nation. Enter your home value for an instant, free calculation.
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Illinois has the second-highest effective property tax rate in the nation at 2.08%, trailing only New Jersey. The state's heavy reliance on property taxes stems from the combination of a flat-rate income tax that limits state revenue and the sheer number of local taxing bodies — over 8,000 — more than any other state. These include counties, cities, school districts, park districts, library districts, fire protection districts, and even mosquito abatement districts, all of which levy their own property taxes.
Illinois property taxes are calculated through a multi-step process that can be confusing, especially in Cook County where the rules differ from the rest of the state.
First, a local township assessor (or the Cook County Assessor in Cook County) determines the fair market value of your property. In most of Illinois, the assessed value is set at 33.33% (one-third) of fair market value. So a home worth $300,000 has an assessed value of $100,000. Cook County is unique — it assesses residential property at just 10% of market value, but then applies a state equalization factor (3.0355 for 2024) that brings the effective assessment closer to the statewide level.
Second, the county clerk applies any applicable homestead exemptions, which reduce the equalized assessed value (EAV). The General Homestead Exemption alone can reduce your EAV by $6,000 to $10,000 depending on your county.
Third, the local tax rate is applied to your net EAV. Your total rate is the sum of levies from every taxing district that covers your property — often 10 or more overlapping districts. This is why two homes just a few miles apart can have very different tax rates if they fall in different school or park districts.
The Property Tax Extension Limitation Law (PTELL), commonly called the "tax cap," limits how much a taxing district's total property tax revenue can grow each year — typically the lesser of 5% or the prior year's CPI increase. It's important to note that the PTELL does not cap individual tax bills or assessments. If your home's value rises faster than others in your district, your share of the capped levy increases even though the district's total revenue is limited.
| Home Value | Estimated Annual Tax | Monthly (Escrow) |
|---|---|---|
| $250,000 | $5,200 | $433/mo |
| $239,000 (median) | $4,971 | $414/mo |
| $600,000 | $12,480 | $1,040/mo |
Illinois offers several exemptions that reduce your equalized assessed value (EAV) before the tax rate is applied. You must own and occupy the property as your principal residence on January 1 of the tax year to qualify for most homestead exemptions.
If you believe your property is assessed above fair market value, Illinois provides a formal appeal process. Start by contacting your township assessor's office (or the Cook County Assessor's Office in Cook County) for an informal review — many disputes are resolved at this stage.
If the informal review doesn't resolve the issue, file a written complaint with your county Board of Review. Most counties give you 30 days from the date of your assessment notice to file. The Board of Review will hold a hearing and issue a decision. If you disagree with their ruling, you have two options: file a written appeal with the State Property Tax Appeal Board (PTAB), or file a tax objection complaint in circuit court. You must first exhaust the Board of Review process before using either route. No attorney is required for the Board of Review or PTAB, though hiring one may be worthwhile for high-value properties.
Illinois property tax due dates vary by county, which is different from most states. In Cook County, taxes are paid in two installments: the first (estimated at 55% of the prior year's bill) is typically due around March 1, and the second installment is due around August 1. In most other counties, the first installment is due in June and the second in September, though exact dates vary. Tax bills are mailed by your county treasurer. Late payments are subject to a 1.5% monthly penalty. If you pay through a mortgage escrow account, confirm with your lender that payments are being made on time — the county holds the homeowner responsible regardless of escrow arrangements.
Property tax rates vary dramatically across Illinois' 102 counties. The collar counties surrounding Chicago (Lake, DuPage, Kane, Will, McHenry) consistently rank among the highest in the entire nation, with effective rates above 2%. Southern and rural Illinois counties tend to have much lower rates but also lower home values. See the full county breakdown below.
You'll see Illinois' effective rate cited as anywhere from 1.73% to 2.23% depending on the source. This calculator uses a 2.08% rate from the U.S. Census Bureau's 2024 American Community Survey 5-Year Estimates — calculated as median property taxes paid divided by median home value. Some sources cite lower numbers because they use older data vintages or weight differently across counties. The Tax Foundation's most recent analysis ranks Illinois second nationally. Because of the enormous variation across Illinois' 102 counties and 8,000+ taxing districts, any single statewide number is an approximation. Your actual tax depends on the specific districts covering your property.
The table below shows effective tax rates, median home values, and median annual property tax payments for ten of Illinois' most notable counties — covering the Chicago metro, major downstate cities, and the state capital. Lake County carries the highest median annual bill in the state at $8,943, while Sangamon County (Springfield) offers a much lower effective rate despite being the seat of state government.
| County | Major City | Effective Rate | Median Home Value | Median Annual Tax |
|---|---|---|---|---|
| Cook | Chicago | 1.89% | $336,000 | $6,349 |
| DuPage | Naperville / Wheaton | 1.91% | $409,100 | $7,812 |
| Lake | Waukegan / Highland Park | 2.43% | $368,000 | $8,943 |
| Will | Joliet / Plainfield | 2.12% | $292,000 | $6,190 |
| Kane | Aurora / Elgin | 2.30% | $313,900 | $7,219 |
| McHenry | Crystal Lake / Woodstock | 2.18% | $299,500 | $6,529 |
| Winnebago | Rockford | 2.58% | $148,200 | $3,824 |
| Sangamon | Springfield | 1.81% | $158,600 | $2,871 |
| Peoria | Peoria | 2.10% | $134,500 | $2,825 |
| Champaign | Champaign / Urbana | 1.93% | $197,800 | $3,818 |
Source: U.S. Census Bureau, 2024 American Community Survey 5-Year Estimates and SmartAsset county-level data. Effective rates = median taxes paid ÷ median home value. Actual rates vary by municipality, school district, and special taxing districts within each county.
Cook County is the most populous county in Illinois with over 5 million residents and contains more than 130 municipalities including Chicago. Despite being the state's largest county, Cook's 1.89% effective rate is actually below the state average — partly because of Chicago's large commercial tax base and partly because Cook County uses a unique classification system that assesses residential property at 10% of market value (compared to 33.33% statewide). However, the state equalization factor of 3.0355 largely offsets this lower assessment ratio. The median homeowner pays $6,349 annually. Tax bills in Cook County arrive in two installments, with due dates around March 1 and August 1.
Lake County has the highest median property tax bill in the entire state at $8,943 per year, driven by an effective rate of 2.43% and median home values of $368,000. The county stretches along the Wisconsin border north of Chicago and includes affluent communities like Lake Forest and Highland Park alongside more modest cities like Waukegan and North Chicago. The county's high tax burden reflects well-funded school districts and municipal services. Lake County residents should pay close attention to exemptions — the General Homestead Exemption ($8,000 EAV reduction as a collar county) and Senior Citizens Homestead Exemption can provide meaningful relief.
Winnebago County has one of the highest effective rates in the state at 2.58%, but much lower home values than the Chicago suburbs — the median is just $148,200. This creates a challenging combination: homeowners face a high rate on relatively modest properties, with a median annual bill of $3,824. Rockford's tax rate reflects the same structural challenge seen in many older industrial cities across Illinois, where a declining tax base has pushed rates higher to maintain services.
Illinois' 2.08% effective rate is the second highest in the nation — more than double the 0.89% national average. Here's how neighboring states compare: