How does this calculator compute the number, and what does it leave out?
Updated 2026-07-28.
A tool that will not say what it cannot know is more useful than one that fills the gap with a plausible number.
What does it compute?
One multiplication, done honestly. The tool takes a DOF market value, finds the band that value falls in, and applies that band's rate to the whole value. The Phase One ladders below are in effect for fiscal years 2026-27 and 2027-28, taken from the DOF surcharge page and the adopted rule.
| Property type | DOF market value | Rate |
|---|---|---|
| Condos and co-ops | $1M to $3M | 4.00% |
| Condos and co-ops | $3M to $5M | 5.25% |
| Condos and co-ops | Over $5M | 6.50% |
| 1-3 family homes | $5M to $15M | 0.80% |
| 1-3 family homes | $15M to $25M | 1.05% |
| 1-3 family homes | Over $25M | 1.30% |
For a cooperative, the tool imputes the unit value the way the statute does: building market value multiplied by the unit's shares divided by total shares, under Administrative Code 11-3205(f). That is the third input mode, and it exists because a shareholder does not have a DOF market value of their own to type in.
What does it not compute?
- Phase Two amounts. From July 1, 2028 co-ops and condos move to comparable-sales valuation, with a single $5 million threshold and the Class 1 rate ladder. The valuation itself changes, so any Phase Two figure produced today would be a guess dressed as arithmetic.
- Abatements, credits, and exemptions. They are not modeled, and they would not change the result: existing abatements, credits and exemptions do not offset the surcharge.
- Penalties and interest. Materially inaccurate certifications carry their own consequences under the rule, and none of that is estimable from a market value.
How current is this?
Rates were last checked against the sources listed below on July 28, 2026. The ladders live in one place in this codebase and the tool reads them from there, so the page and the calculator cannot drift apart.