Guide
How to appeal your Cook County property tax
Cook County homeowners can appeal their property assessment every year — for free, online, and without a lawyer. Whether you live in Chicago (Jefferson, Lake View, Rogers Park and other city townships) or the suburbs (Oak Park, Evanston, Berwyn, Cicero and beyond), here's how a Cook County tax appeal works, in plain English.
The short version
- Check free whether your home is over-assessed compared to similar homes.
- File online with the Assessor during your township's window (about 30 days).
- If needed, file again with the Board of Review later in the year.
- PTAB is the optional state-level last step.
Step 1: Check whether your home is over-assessed
Before you spend time on an appeal, find out if it's worth it. The most common winning argument is that your home is assessed higher per square foot than similar homes nearby — a "lack of uniformity" argument.
Enter your address or 14-digit PIN in our free check. We pull your property's official Cook County records and compare your assessed value per square foot with similar homes in your neighborhood. If your assessment looks in line, we'll tell you — no sales pitch.
Step 2: Appeal to the Cook County Assessor
The Assessor is the first and usually best place to appeal. Each township opens for appeals for a limited window — typically about 30 days — and townships open at different times throughout the year.
File online at the Assessor's website during your township's window. You'll state your grounds (uniformity is the most common for homeowners) and submit evidence: your home's details plus comparable nearby homes with lower assessments per square foot.
Missing your township's Assessor window doesn't end your options — you can still appeal to the Board of Review later in the year.
Official site: Cook County Assessor
Step 3: Appeal to the Cook County Board of Review
The Board of Review is the second stage. It also opens by township, in groups, later in the year — and you can appeal here even if you skipped (or lost) the Assessor stage.
The process is similar: file online during your township's window with your comparable-home evidence. The Board can lower your assessed value even if the Assessor didn't.
Official site: Cook County Board of Review
Step 4: PTAB — the state level (optional)
If both county offices turn you down, you can appeal to the Illinois Property Tax Appeal Board (PTAB). This is a state-level review with its own deadline — generally 30 days after the Board of Review's final decision for your township.
PTAB appeals are more formal, but homeowners do file them without a lawyer. For most people, the Assessor and Board of Review stages are where the realistic savings are.
Deadlines depend on your township
Every township has its own Assessor and Board of Review windows, and they change each year. We track the official calendars for all Cook County townships.
See my township's deadlinesWant the paperwork done for you?
Our $79 appeal kit turns your free check into a ready-to-file package: a plain-English argument with your numbers, your comparable homes and recent sales, a worksheet with every value to type into the official online form, and step-by-step filing instructions for your township's current window. It comes with a 12-month refund promise — if you appeal and your assessment isn't reduced, you can request a refund.
Start with the free check