How to appeal your Cook County property taxes yourself

What an appeal can and can't do

An appeal asks the county to correct the value it put on your home. It does not challenge your tax rate or the levies set by local taxing bodies. The Assessor's office says it does not set levies, rates or bills.

A lower assessment can lead to a lower bill, but not one-for-one. Your bill also depends on exemptions, the total assessed value of your community and local levies. An appeal can also end with no change at all.

The Assessor offers a rule of thumb: if the characteristics on your notice are correct and the estimated market value is within 10 percent of what you think your home is worth, an appeal is unlikely to change your bill much. If the value looks high or the facts about your home are wrong, it is worth a closer look.

Two free chances: the Assessor, then the Board of Review

Cook County homeowners can appeal in two places. First the Cook County Assessor's Office (CCAO), during your township's window. Then the Cook County Board of Review (BOR), which opens townships after the Assessor has finished assessing them.

You can use both. The Board of Review says it is not bound by the Assessor's decision, and you are at no disadvantage whether the Assessor granted or denied a reduction. After the Board of Review, the next options are the state Property Tax Appeal Board (PTAB) or the Circuit Court.

Filing is free at both offices. For a comparison of the two, see Assessor vs Board of Review.

Find your deadline

Each of Cook County's 38 townships has its own appeal window. Your Assessor deadline, the "Last File Date," is printed on your reassessment notice and posted on the Assessor's calendar. Board of Review dates are published separately, township by township.

Treat these dates as hard deadlines. The Assessor's rules say it will not accept any appeal or supporting documents after the township closing date, except in cases of a CCAO system error. The Board of Review's rules say no complaint is accepted after a township's filing period has closed.

In 2026 the south and west suburbs were reassessed. Townships in the north suburbs and the City of Chicago were not reassessed this year, but they still have appeal windows. Our deadlines page by township tracks both sets of dates.

Gather your evidence first

The Assessor lists three common reasons homeowners appeal:

• Uniformity. Similar homes in your neighborhood are assessed lower than yours. For appeals based on comparables, the Assessor's rules ask for at least 3 comparable properties, recommend at least 5, and require the PIN of each. See our guide to picking comparables.
• Overvaluation. Your home is worth less than the Assessor's estimate. Recent closing statements or the sale prices of similar homes are typical evidence, and any appraisal must be USPAP compliant.
• Incorrect information. The Assessor's record has the wrong square footage or other characteristics. Dated photos, a property deed or similar documents can support the correction.

Before you file, look up your property details on the Assessor's website. Its rules ask you to review them and to state clearly in your appeal if anything is wrong. A free check of your home against similar homes can show whether your assessment stands out.

Step by step: file online, then at the Board of Review

These steps follow the Assessor's SmartFile guide and the Board of Review's instructions for homeowners. Screens can change from year to year, so read each page as you go.

1. Confirm your township is open. Check the Assessor's appeal calendar or the date printed on your reassessment notice. The Assessor warns that starting a filing before your township opens may result in a deleted file.
2. Create a SmartFile account. Open the Assessor's SmartFile site and click "New User? Create an account." Enter your email and a password of at least 8 characters, then click the link in the activation email (check your spam folder).
3. Start a Residential appeal. Under Available Filings, choose the Residential filing (single-family homes, townhomes and buildings with up to six units; condos use the Condo/Coop filing). Search by your 14-digit PIN or address and click Start Filing.
4. Work through the tabs. Confirm the parcel, choose Taxpayer/Owner as the filer, and correct any wrong property characteristics. On the Appeal Application tab, pick your reason, add a short explanation and enter the market value you believe is right, which is required.
5. Add comparables and documents. If you chose lack of uniformity, the built-in comparables tool lets you add up to 5 similar properties. On the Attachments tab, upload supporting documents such as a closing statement, dated photos or a short written explanation.
6. Sign and submit before the Last File Date. Type your name as your electronic signature and add a phone number. After you click Submit you cannot edit the filing, but while your township is still open you can add documents through the "Attach Additional Documents" filing.
7. Watch your email and your mailbox. You get a confirmation email, then a second email with your appeal docket number. The Filing ID in the first email is not your docket number. The Assessor sends the result by mail.
8. If you disagree, file with the Board of Review. When the Board of Review opens your township, file a complaint through its online portal. You can pre-register before your township opens with your township, name, property address and PIN.
9. Send your Board of Review evidence on time. The Board's rules ask for a brief that includes a color photo of the front of your home taken within the previous 12 months, plus your comparables or sale documents. You choose at filing whether to request a hearing; it is optional.

What happens at the Board of Review

The Board of Review is a separate, quasi-judicial agency. Its decision sets the final county valuation on your property for that tax year. Self-represented hearings are held by phone.

A hearing is optional, and the Board says you will not be penalized for waiving it. Its analysts do the same review whether or not a file gets a hearing. The Board says people typically attend when their appeal has unique elements that can't be conveyed in writing.

Evidence is due by a date the Board sets after your township closes. In the 2026 schedule published so far (township groups 1 and 2), that date was 10 days after the township closed. If you think the decision is wrong, the Board accepts a written "Re-Review" request within 3 days of the decision letter, on specific listed grounds only.

Beyond that, see appealing to PTAB after the Board of Review.

When a change would show up on your bill

The Assessor says changes from a reassessment show up on your second-installment bill in the following year. A 2026 assessment change would affect the bill issued in 2027.

Keep paying on time while you wait. The Board of Review notes that the first installment is 55% of the previous year's total bill, and the second-installment bill is not issued until the Board has finished all 38 townships.

Doing it yourself, with or without help

The Assessor says you do not need to hire anyone to appeal and that filing online can take as little as 20 minutes. At the Board of Review, only you or a licensed attorney can appear for a home titled in your name; a consultant may not represent a homeowner there.

If you would rather not assemble the paperwork from scratch, Cook Tax Check offers an optional document packet ($49, refunded if the county says no). You still file it yourself, for free, on the county site.