Cook County Composite Tax Rates (2025): How to Estimate Your Property Tax Bill
By Harsha N Hegde
After your property’s assessed value is equalized, the composite tax rate determines what you actually pay in property taxes.
This guide explains how Cook County’s composite rates are calculated, what they include, and how to estimate your 2025 tax bill.
Formula Recap
Property Tax = (EAV − Exemptions) × Composite Tax RateThe composite rate converts your equalized assessed value (EAV) into actual taxes owed. It’s expressed as a percentage of EAV, not market value.
What is a Composite Tax Rate?
The composite tax rate is the sum of all tax rates from the overlapping taxing bodies that serve your area — school districts, municipalities, park districts, libraries, and the county itself.
Each taxing body sets a levy; the Cook County Clerk adds them up and divides by total EAV in each district.
Who sets it?
The Cook County Clerk’s Office calculates the composite tax rate each year based on levies submitted by all local taxing districts.
The formula used by the Clerk is:
Composite Rate = (Total Levy of all Taxing Districts) ÷ (Total Equalized Assessed Value)You can find official reports on the Cook County Clerk’s website.
2025 Example: Chicago vs. Suburbs
| Township | 2025 Estimated Composite Rate | Change from 2024 | Notes |
|---|---|---|---|
| Chicago | 6.65% | +0.1% | Includes City + CPS levy |
| Evanston | 7.10% | +0.3% | Strong school component |
| Schaumburg | 8.25% | +0.2% | Multiple overlapping districts |
| Thornton | 12.40% | +0.6% | Heavy school + special levies |
(Actual 2025 rates pending release; based on 2024 trend data.)
Why suburban rates are higher
Suburban areas often have multiple smaller taxing districts and fewer commercial properties to share the burden.
Chicago’s broader tax base and higher property values generally keep its composite rate lower.
Example Calculation
Let’s calculate a typical suburban homeowner’s tax bill.
EAV: $90,000
Exemptions: $18,000
Taxable EAV: $72,000
Composite Rate: 8%
Property Tax = 72,000 × 8% = $5,760Your actual bill may differ depending on your township’s rate and exemptions.
How to Find Your Township’s Composite Rate
- Go to the Cook County Clerk’s Tax Rate Finder.
- Choose the latest Tax Rate Report for your township or municipality.
- Find your tax code on your property tax bill and match it to the composite rate in the report.
How It Connects to EAV
Your property’s Equalized Assessed Value (EAV) determines what portion of its market value is taxable.
Your composite rate determines how much you pay on that taxable portion.
See our guide on Equalized Assessed Value (EAV) in Illinois to understand how your EAV is calculated before tax rates apply.
FAQs
What causes composite tax rates to change each year?
Rates rise or fall depending on the total levy requests from taxing districts and the county’s total EAV. If EAV rises faster than levies, rates may go down—and vice versa.
Why are South Suburban rates so high?
South suburban areas often have shrinking EAV and heavy reliance on school funding, causing higher composite rates to meet levies.
Do exemptions lower my tax rate?
No. Exemptions reduce your taxable EAV, not the composite rate itself—but the effect is similar: they lower your final tax bill.
Are composite rates the same across Chicago?
No. The rate can vary slightly depending on your tax code and overlapping districts, even within the City of Chicago.
About the Author
Harsha N Hegde is the founder of squaredeal.tax, a DIY platform that helps homeowners protest unfair property tax assessments. He has helped thousands of homeowners save money using comps-based evidence and practical guidance.
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