Property tax
The market value your assessment implies, tested against your own comps, with the filing priced.
Market value the roll implies
Computed
The roll
From the notice, not the market estimate the county's website shows.
Tax paid divided by market value. Your bill is the authority.
Most boards charge nothing for a residential petition.
Zero if you file yourself. Representatives charge a share of the first year.
Your property
Your comps, adjusted to your house
| Comp | Sale | Δ size | Δ features | Adjusted |
|---|---|---|---|---|
| #1 | $215,000 | $0 | $0 | $215,000 |
| #2 | $225,000 | $0 | $0 | $225,000 |
| #3 | $220,000 | $0 | $0 | $220,000 |
Adjustment rate: $100 a square foot, taken from your own sales. A comp older than twelve months is flagged, not excluded.
The filing, priced
The engine does not source comparables and will not invent them. The strength of the petition is the strength of the sales you type in.
An assessed value divided by the statutory ratio is the county’s own opinion of what the house is worth. In a state that assesses at 40%, a $100,000 assessment is a $250,000 claim. Most owners have never seen their number written that way, which is why the appeal rate is under five percent.
Three to six sales you supply are brought to your house’s features at explicit rates — per square foot, per bedroom, per bathroom, per garage stall. Every adjustment is visible and editable, because the petition is only as strong as the evidence in it and you are the one who has to defend that evidence.
It does not source comparables. There is no feed behind this page and inventing sales would be fabrication with a spreadsheet around it. It also declines to rule on fewer than three comps, and declines to model a jurisdiction it does not carry.
implied value = assessed value / assessment ratio
adjusted comp = sale price + size Δ + feature Δ
excess = implied value − median(adjusted comps)
annual delta = excess × effective rate
NPV = Σ delta / (1 + d)^t − filing fee − contingency
Eight jurisdictions carry a statutory ratio here: Texas, California, Cook and non-Cook Illinois, Ohio, Georgia, New York municipalities and Montgomery County, Maryland. Elsewhere the engine refuses rather than substituting a national average.