The local tax guide · Illinois
Cook County
property tax, explained.
A Chicago home and a suburban Cook County home can have different local tax rates. Start with the parcel’s taxable equalized assessed value and its own tax rate—not a county average or the home’s sale price.
Sources reviewed
Follow the dollars
What a 7% local rate actually applies to
For an illustrative taxable EAV of $100,000 and a local rate of 7%, tax is $100,000 × 0.07 = $7,000. This is not the tax on a $100,000 market-value home. Both inputs must come from the same tax year before using this as a bill check.
Annual tax from your taxable EAV and entered local rate. Excludes penalties, interest and adjustments not reflected in those inputs. This is not a second-installment amount.
Use the inputs from your record
Cook County tax calculator
Annual illustration
$7,000.00
Using the starting example inputs.
- Taxable base
- $100,000.00
- Value-based tax
- $7,000.00
Annual tax from your taxable EAV and entered local rate. Excludes penalties, interest and adjustments not reflected in those inputs. This is not a second-installment amount.
Match the value and rate year. Calculations happen in your browser; this form does not submit your inputs.
Follow the value from assessment to bill
Cook’s Class 2 residential assessment starts at 10% of estimated market value. The state equalizer is then applied, followed by eligible exemptions, before the local rate determines the tax. The county’s property tax process explains that sequence.
Open the Cook County Property Tax Portal and identify your Property Index Number (PIN). Match the PIN, tax year, assessment, exemptions and local rate to your bill. The Treasurer’s annotated 2024 bill (PDF) shows where those fields appear; its year-specific figures are not current defaults.
A useful check: multiplying market value directly by the local EAV rate skips the assessment process and greatly overstates the result. Conversely, multiplying an already-taxable EAV by the equalizer again counts equalization twice.
An exemption reduces taxable value, not dollar-for-dollar tax
The Cook Homeowner Exemption reduces eligible EAV by $10,000. At the illustrative 7% rate, that would save $700—not $10,000. If your entered taxable EAV already includes the exemption, no additional subtraction belongs in the calculator.
Check the exemption entries on the bill before assuming that a higher bill means a higher assessment. A missing exemption is a different problem from an incorrect property valuation. Use the assessor’s eligibility and application instructions; do not assume a seller’s exemption automatically establishes your eligibility.
Match the problem to the right office
For property characteristics, assessments or exemption questions, start with the Cook County Assessor. For the billed balance and payment history, use the Cook County Treasurer. The Board of Review is a separate assessment appeal office.
Identify your township and tax year before checking the assessor’s assessment calendar. Keep the property record, any factual errors and supporting comparable properties together. Do not treat a general inquiry as a filed appeal, or assume all townships share one deadline.
Compare annual totals before comparing installments
The Treasurer’s bill guide distinguishes the estimated first installment from the final second installment. The calculator shows an annual amount; subtract payments and account for bill adjustments before interpreting what remains due.
When a bill changes, compare the same fields in both years: taxable EAV, exemption entries and local rate. That separates a valuation change from lost relief or a rate change, and gives the appropriate office a specific question to answer.
Sources and review scope
Property Tax Almanac checked these official sources on September 26, 2026. Illustrative inputs are labeled; this review does not establish every parcel’s current rate or individual eligibility.
- Cook County property tax process — Assessment, equalization, exemptions and local rates.
- Homeowner Exemption — $10,000 EAV reduction and local-rate savings calculation.
- Annotated 2024 second-installment bill (PDF) — Historical bill layout, assessment level and installment distinction; not a current rate source.
The calculator divides the taxable base by 100, multiplies by the entered rate and rounds to cents. It is a bill-checking tool, not an official tax determination. Other site tools may use different benchmark assumptions.
Report a correction with the page, tax year and official source. See our data methodology or return to Illinois counties.