Cook County Property Tax Calculator
Cook County reassesses property on a triennial cycle, meaning your assessed value is set fresh only once every third year rather than annually, with the two years in between typically holding steady absent a successful appeal or major change to the property. The Cook County Assessor's Office handles that valuation, and Illinois as a whole carries some of the country's higher effective property tax rates. Choose Cook County from the list above, then add a home value to preview your bill.
Annual Property Tax
$5,627Monthly (Escrow)
$469Effective Rate
1.73%Cook County's effective rate (1.73%) is 8% lower than the Illinois average (1.88%).
Edit inputs ↑Cook County Effective Rate
1.73%
Vs. Illinois Average
8% lower
Illinois National Rank
#2 of 51
1 = highest statewide rate
County Median Home Value
$324,500
Estimated Annual Tax (Median Home)
$5,627
Monthly Equivalent
$469
Property tax in Cook County, Illinois
- Rather than a fresh number every year, the Cook County Assessor's Office runs a triennial cycle, so your figure typically only resets once every three years.
- Owners can appeal a new assessment first with the assessor's office, then with the county's Board of Review if they remain unsatisfied.
- Illinois consistently ranks among the states with the highest effective property tax rates, and Cook County's rates track that pattern.
- Exemptions exist for a primary residence, seniors, and other qualifying owners, reducing the taxable portion of an assessed value.
Other large Illinois counties
Effective rate = aggregate real-estate taxes paid ÷ aggregate home value (ACS 2024 5-year).
| County | Effective Rate | Median Home Value |
|---|---|---|
| DuPage County | 1.89% | $391,400 |
| Kendall County | 2.28% | $322,400 |
| Winnebago County | 2.28% | $164,500 |
| Lake County | 2.26% | $345,700 |
| McHenry County | 2.26% | $308,100 |
| DeKalb County | 2.25% | $243,600 |
See property tax across every county in Illinois at the Illinois property tax calculator , or check your Illinois income tax with the Illinois income tax calculator .
Frequently asked questions
How is property tax calculated in Cook County?
The Cook County Assessor's Office pins your figure on a triennial reassessment cycle, and local taxing bodies — schools, municipalities, park districts, and others — each layer their own levy on top. Illinois's generally high effective rates mean that underlying figure matters a great deal here.
How do I appeal my Cook County assessment?
The assessor's office is the first stop for a challenge, and a further appeal goes to the county's Board of Review if a settlement isn't reached there. Both levels want comparable sales or similar proof that the number is off.
Does Cook County offer a homestead exemption?
Yes — Illinois provides several breaks for a primary residence, plus extra relief for seniors and other qualifying owners, each shaving down what local rates get applied to.
Why does my Cook County assessment only change every few years?
Cook County uses a triennial reassessment schedule, so unlike jurisdictions that reassess annually, your value is typically only reset once every three years unless you successfully appeal or the property changes significantly in the interim. That's also why appealing during your township's reassessment year carries extra weight.
Sources
Related insights
Use these guides for rule explanations, planning context, and follow-up questions beyond the calculator result.