What is the difference between an unequal and an excessive assessment in New York?

New York's grievance grounds are spelled out in N.Y. RPTL §524: an assessment may be challenged as excessive, unequal, or unlawful, or because the property is misclassified. For homeowners, the two that matter most are excessive and unequal.

Excessive assessment. Your assessed value (after applying the town's level of assessment) reflects a market value higher than your property is actually worth. You prove it with comparable sales — recent arm's-length sales of similar nearby homes — or a recent purchase price or appraisal of your own home. If similar houses sold for $350,000 but your assessment implies $420,000, that is an excessive-assessment claim.

Unequal assessment. Your property is assessed at a higher percentage of market value than other properties in the same assessing unit. You prove it using the residential assessment ratio (RAR) or equalization rate: multiply your home's market value by the RAR to get an equitable assessment, and show your actual assessment exceeds it. Example: $400,000 market value × a 2.5% RAR = $10,000 equitable assessment; if you are assessed at $12,500, you have an unequal claim even if $400,000 is a fair value.

You can claim both. Form RP-524 lets you assert excessive and unequal grounds on the same complaint, and many successful grievances do. The BAR will grant relief on whichever ground yields the larger justified reduction.

Unlawful and misclassified are narrower: unlawful covers assessments on exempt property or outside the taxing jurisdiction; misclassified covers a wrong property-tax class (e.g., Class 1 vs Class 2). See RPTL §525 for how the board weighs each ground.

For most over-assessed homeowners, lead with excessive (comp sales) and add unequal (RAR math) as a backstop.