In New York, where you live decides when you fight. NYC owners appeal to the Tax Commission by early March. Nassau has its own calendar. Almost everyone else files Form RP-524 by Grievance Day — the fourth Tuesday in May. Our free tools work for all of them.
NYC → Tax Commission (TC forms) after your January NOPV. Nassau → ARC. Everywhere else → Form RP-524 to your local Board of Assessment Review by Grievance Day.
NYC publishes every parcel's assessment on its Open Data portal — our free scraper pulls comps by neighborhood. Upstate, most counties offer online parcel search (ImageMate and similar).
Unequal assessment and excessive assessment are the workhorse grounds. Attach your comps worksheet. Filing with the BAR is free; you can appear on Grievance Day or just file in writing.
Denied? Homeowners can file Small Claims Assessment Review — $30, informal hearing, no lawyer needed — within 30 days of the final roll.
The NYC Charter fixes Tax Commission deadlines: March 2, 2026 for Class 2, 3 & 4 and March 16, 2026 for Class 1 homes. Miss it and you wait a full year. Outside NYC, verify your town's Grievance Day — some counties (e.g., Suffolk: third Tuesday in May) differ from the statewide default.
Everything runs in your browser — we never see or store your property data.
New York municipalities assess at widely varying fractions of market value (the equalization rate); NYC Class 1 homes are assessed at 6% with capped growth. Divide your assessment by your equalization rate to estimate implied market value. The 1.54% default approximates the statewide average effective rate — Long Island and Westchester run far higher. Estimates only; not tax advice.
Enter recent sales of similar homes (or import a CSV from our free NYC Open Data scraper). The worksheet computes price per square foot and a suggested value for your property.
| Address | Sale Date | Sale Price ($) | Sq Ft | $/Sq Ft |
|---|
| Item | New York Rule |
|---|---|
| NYC (5 boroughs) | Appeal NOPV to the Tax Commission — 2026: March 2 (Classes 2–4), March 16 (Class 1). Forms TC101/TC108 |
| Nassau County | Assessment Review Commission — its own window (typically Jan–Mar); then SCAR |
| Rest of state | Form RP-524 to your Board of Assessment Review by Grievance Day — 4th Tuesday in May (May 26, 2026); Suffolk: 3rd Tuesday |
| Grounds | Excessive · Unequal · Unlawful · Misclassified |
| Next level (homeowners) | SCAR — $30 filing fee, within 30 days of final roll filing |
| Records — NYC | NYC Open Data: assessment roll & PLUTO datasets, free API (see our scraper) |
| Records — upstate | County parcel portals (ImageMate/SDG and similar) + NYS ORPTS equalization rates |