About PropGap
Independent property tax data for homeowners everywhere.
Built to Bridge the Gap Between Unfair Assessments and Verified Market Data
New Jersey homeowners pay the highest property taxes in the nation — average bills now exceed $9,800 per year. In Texas, appraised values rose dramatically from 2020–2024, pushing millions of homeowners into over-assessed territory. Yet the tools to challenge these assessments were only available to tax attorneys charging $1,000–$3,000 per appeal.
PropGap was built to change that. We take the same comparable sales data that tax professionals use — real transaction prices of similar nearby homes — and organize them into a clear, formatted evidence packet that any homeowner can understand and present to their local Board of Taxation or Appraisal Review Board. No law degree required.
What is an Assessment Gap?
In New Jersey and Texas, an assessment gap is the difference between your assessed value and what similar homes in your neighborhood actually sold for. Your tax bill only shows your property's numbers — not how they compare to recent real-world sales nearby.
In NJ, if your assessed value exceeds the median comparable sale price, you're paying taxes on an over-stated value. In Texas, the unequal appraisal standard under §41.43 means even a “fair market value” assessment can be challenged if comparable homes are valued lower.
PropGap makes this gap visible by pulling recent comparable sale prices and comparing them to your assessed value — using the same evidence standard that Boards of Taxation and Appraisal Review Boards actually evaluate.
What PropGap Does
PropGap is a property data research tool. We pull recent comparable sale prices for homes similar to yours, identify any gap between those sale prices and your assessed value, and format the evidence in the structure that NJ and TX appeal boards evaluate.
Our Evidence Packet gives you the same data points that tax professionals use to build an appeal argument — without the $1,000+ attorney fee. You review, you decide, you file (or don't).
- Up to 20 recent comparable sales pulled from your neighborhood
- Median comp market value vs. your assessed value — the NJ Chapter 123 standard
- Texas unequal appraisal evidence (§41.43) for protest hearings
- State-specific forms: pre-filled NJ Form A-1 or TX Form 50-132 (Filing Packet)
What PropGap is NOT
We are not a law firm, government agency, or licensed appraisal service. We do not file appeals on your behalf. We do not guarantee assessment reductions.
PropGap provides independent data research. You are responsible for deciding whether to file an appeal and for submitting it to your local tax appeals board or assessor's office.
Our Data
PropGap uses publicly available property assessment records and licensed property data APIs. All assessment values, market values, and property characteristics come from official public records.
We encourage every user to verify their data directly with their local assessor's office. Our reports include source attribution and timestamps so you know exactly where the data came from.
Ready to Check Your NJ or TX Assessment?
Free preview — see your comparables in 30 seconds. Evidence Packet $49 if over-assessed.
Research Your Property