We make published county assessment records readable, and show the arithmetic instead of asking you to trust a prediction.
You enter an address. We compare that property's assessment against comparable properties nearby, using the county's own published records, and tell you whether the assessment looks out of line — and by how much. The analysis is free and needs no account.
If there is a case worth making, you can buy the completed filing packet. If there is not, we say so. A verdict of "not worth filing" is a useful answer, and it is the one we return most often.
A property tax appeal is decided by a board of review reading evidence. Software that produces a conclusion without showing how it got there is no use in front of that board. So every analysis prints the comparable properties it used, the assessment per square foot for each, the median, and the arithmetic that produced the proposed figure.
You can check our work. That is the point.
County assessor records, published openly by the counties themselves, normalised into one dataset — currently around five million Illinois parcels. The hard part of this product is not writing text. It is that 102 counties publish inconsistent records in different vocabularies, and a comparable is only meaningful if the parcels either side of the comparison are genuinely alike.
We are not a law firm, and this is not legal advice. We do not file on your behalf, we do not appear before a board, and we do not appraise property. We produce evidence and a completed form; you file it.
We do not guarantee an outcome. No one honestly can — the decision belongs to the board of review, and it turns on evidence, deadlines and local practice.
In Cook County an individual may represent themselves. An entity such as an LLC or a corporation generally requires an Illinois attorney, both at the Board of Review and at the Property Tax Appeal Board. If you own the property through an entity, take advice.
ParcelProof is built and operated by Zappfin LLC, based in Illinois. It is a small, self-funded team. Questions reach a person: support@parcelproofai.com.
If a packet is not useful to you, write to us and we will refund it. No reason required, no time limit. An $10.99 document should not require a negotiation.