What makes a good Cook County property tax appeal comp?
Finding a property assessed for less than yours is easy. Finding one similar enough to support a credible appeal is the part that matters.
See what the analysis finds on your property.
Enter a Cook County address or PIN. See actual comparable evidence before paying.
Free to check first. No credit card required.
A lower assessment does not automatically make a strong comp.
Cook County's current appeal rules focus on properties that are similar in size, class, characteristics, and location. The Assessor also cautions against cherry-picking only the lowest-valued properties. That means a useful comp needs two things at the same time: it should be favorable and it should remain genuinely comparable.
Similar enough to defend
- same or appropriate neighborhood context
- same residential property class
- similar building square footage
- similar land square footage
- similar age and construction characteristics
- meaningfully favorable assessment
Favorable number, weak comparison
- dramatically lower assessment
- but materially different class or size
- very different age or construction
- different location context
- unusual property characteristics
- selected mainly because the number looks good
Find favorable evidence that still looks credible when someone asks, “Is this house actually comparable to mine?”
Comparability is more than a neighborhood and a class code.
The Cook County Assessor's current guidance identifies location, property class, age, building square footage, land square footage, and other construction characteristics as relevant to comparability. Its 2026 appeal rules require at least three comps for a comp-based appeal and recommend at least five.
The Board of Review uses the same practical idea for lack-of-uniformity cases: compare the subject with similar properties, then evaluate the assessment per square foot rather than relying on a low number in isolation.
Why the strongest match may not have the largest percentage.
A nearly identical home assessed 10% lower can be more persuasive evidence than a much less similar property assessed 25% lower. Similarity establishes whether the comparison deserves weight. The favorable assessment shows the potential uniformity issue.
The comparable is useful because the physical match and the lower building-rate assessment point in the same direction.
Searching the records is only the first step.
Cook County provides public property records and free tools for finding comparable homes. Simple Tax Appeal does the analytical work on top of those records.
The software evaluates the qualifying set, compares relevant characteristics, ranks the evidence, calculates the requested assessed value the evidence supports, and organizes the result into filing-ready materials.
See the data and methodology →See real evidence before deciding whether to buy.
The free property check tells you whether qualifying comparable evidence exists. After email verification, you can inspect one complete qualifying comparable. The $49 package unlocks the full analysis and filing materials for that property and assessment year.
Verify the record before filing.
Public data can contain errors or lag physical changes. Check each address, PIN, assessment, and material property characteristic against the official Cook County record before relying on it in an appeal.
Check your Cook County property and see the strongest qualifying evidence.
Simple Tax Appeal organizes public-record comparisons and filing materials. It is not an appraisal, legal advice, or a guarantee of an appeal result.