Step 1
The Cook County Assessor determines estimated market value and classification before a bill is ever issued. This is the stage where you should verify basic property facts and decide whether an appeal makes sense.
Estimates market value, applies classification, tracks exemptions, and sends reassessment notices.
Check square footage, building characteristics, property class, recent sales context, and exemption status.
The Assessor does not set tax levies, tax rates, or the final property tax bill.
Official guidance from the Assessor states that if the listed characteristics are correct and the estimated market value is within roughly 10% of what you think the property is worth, an appeal may be less likely to materially change the result.
Estimated market value: what the Assessor believes the property would sell for in the current market.
Assessed value: the taxable value used in the property tax formula. For many residential properties this is generally 10% of market value; for many commercial properties it is typically 25%.
Classification: the property class assigned under county rules, which can materially affect assessment treatment.
Next Step
If your value or characteristics appear inaccurate, move to the appeal stage and prepare your evidence.
