County Tax Calc
Estimates only — for informational purposes. Illinois assessment ratios differ between Cook County and other counties; mill rates vary by taxing district. Verify with your county assessor or the Illinois Department of Revenue.

Illinois Property Tax Calculator

Estimate your Illinois property taxes. Most Illinois counties assess at 33.33% of market value; Cook County uses 10% for residential. Enter your market value, the correct ratio for your county, and your total mill rate.

The Formula

Annual Tax = Taxable Assessed Value × (Mill Rate ÷ 1,000)

Assessed Value = Market Value × Assessment Ratio (state-specific — see note below)
Mill Rate: 1 mill = $1 per $1,000 of assessed value. Enter your actual rate from your county tax bill.

Illinois Property Tax Inputs

Assessment ratio note: Most IL counties: 33.33% of fair market value. Cook County residential: 10% of market value. Cook County commercial: 25%. Source: Illinois Dept. of Revenue, tax.illinois.gov/localgovernments/property.html (as of June 2026).

$
%

Pre-filled with Illinois's common ratio. Verify on your tax bill.

mills

Enter your actual combined mill rate. The pre-filled value is illustrative only.

$

Dollar reduction from assessed value. Check with your county assessor.

Annual Tax
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Monthly (escrow est.)
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Assessed Value
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Effective Rate
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Illinois Property Tax — Key Facts

  • Assessment ratio: 33.33% in most counties; 10% residential / 25% commercial in Cook County. Source: Illinois DOR (June 2026).
  • Equalized Assessed Value (EAV): Your assessed value is multiplied by the county equalization factor (multiplier) to create the EAV, which is the base for calculating taxes and exemptions.
  • Two-year cycle: Property is valued in year 1; tax bills issued in year 2. Bills typically due June 1 and September 1 in most counties.
  • Local administration: The Illinois DOR does not administer property tax — contact your township/county assessor for your assessed value and EAV.
  • Exemptions: Multiple exemptions available (homestead, senior, veterans). Apply with your county assessor.

Source: Illinois Department of Revenue — tax.illinois.gov/localgovernments/property.html (verified June 2026).

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Frequently Asked Questions

What is Illinois's property assessment ratio?

In most Illinois counties, property is assessed at one-third (33.33%) of fair market value. Cook County uses a different classification system: residential property is assessed at 10% of market value, commercial at 25%. Source: Illinois Department of Revenue, tax.illinois.gov/localgovernments/property.html (June 2026).

Who administers property tax in Illinois?

The Illinois Department of Revenue does not administer property tax directly — it is managed by local governments. Township and county assessors set values, county boards of review hear appeals, and county collectors bill and collect taxes. Source: tax.illinois.gov (June 2026).

How does the Illinois property tax cycle work?

Illinois uses a two-year cycle. In year 1, the assessor values the property as of January 1. In year 2, tax bills are calculated and sent. Most counties bill in two installments, typically due June 1 and September 1. Cook County uses an accelerated system.

What exemptions are available in Illinois?

Illinois offers several exemptions that reduce assessed value, including: General Homestead Exemption, Senior Citizen Homestead Exemption, Senior Freeze Exemption, Persons with Disabilities Exemption, and Veterans exemptions. Amounts and eligibility vary by county. Contact your county assessor to apply.