Can I sell unused air rights in NYC?

Usually only to an adjacent lot through a zoning lot merger, or within a few districts that allow transfers over a wider area. The buyer and seller record an agreement.

Does Hercules show unused air rights?

Yes. Every NYC lot report shows the zoning district, FAR and estimated unused floor area, on every plan from Pro up.

Is unused FAR the same as what I can build?

No. It is the zoning ceiling. Height limits, setbacks, the lot's shape and the cost of building decide what is practical.

How to check unused air rights on a NYC lot

The short answer

Unused air rights are the floor area the zoning allows on a lot minus the floor area already built. Multiply the lot area by the maximum floor area ratio (FAR) for its zoning district, then subtract the existing building area. Hercules shows the zoning district, FAR and an estimate of unused floor area for every NYC tax lot, and the free zoning lookup gives a first read by address.

Hercules covers every New York City tax lot, about 858,000 of them (as of 2026-10-14).

The calculation

Find the zoning district and any overlay or special district for the lot.
Take the maximum FAR for the use you plan: residential, commercial or community facility FARs can differ.
Multiply the FAR by the lot area to get the maximum floor area.
Subtract the floor area of the existing building.
What is left is the unused floor area, often called unused air rights.

Example	Value
Lot area	2,500 sq ft
Maximum FAR	4.0
Maximum floor area	10,000 sq ft
Existing building	6,000 sq ft
Unused floor area	4,000 sq ft

An illustration, not a real lot.

What changes the number

Special districts, inclusionary housing and other bonuses can raise the maximum.
Height, setback and yard rules can stop you using all of it.
A landmark or historic district adds review before you build.
Air rights can move to a neighbouring lot through a zoning lot merger, so a neighbour may already have used them.
Zoning text changes, such as the citywide housing changes adopted in 2024, can raise or lower the figure.

A quick screen tells you where to look. Confirm buildable area with an architect or zoning lawyer before you price a deal on it.

Check a lot's zoning free

Questions

Can I sell unused air rights in NYC?: Usually only to an adjacent lot through a zoning lot merger, or within a few districts that allow transfers over a wider area. The buyer and seller record an agreement.
Does Hercules show unused air rights?: Yes. Every NYC lot report shows the zoning district, FAR and estimated unused floor area, on every plan from Pro up.
Is unused FAR the same as what I can build?: No. It is the zoning ceiling. Height limits, setbacks, the lot's shape and the cost of building decide what is practical.