BBL and BIN Explained: NYC Property IDs

A BBL (borough-block-lot) is the 10-digit number New York City uses to identify a tax lot, the piece of land a property sits on; a BIN (Building Identification Number) is a 7-digit number for one building. Records about land, taxes, deeds and sales are mostly keyed to the BBL, while Department of Buildings records are keyed to the BIN, so knowing both lets you pull every city record for an address.

How a BBL is built

The City Planning data dictionary describes the BBL as the borough code, followed by the tax block, followed by the tax lot. The block is padded with leading zeros to five digits and the lot to four. Its own examples:

Borough codes are 1 Manhattan, 2 Bronx, 3 Brooklyn, 4 Queens and 5 Staten Island. Two oddities: Marble Hill is served by the Bronx but legally in Manhattan, so its BBLs start with 1, and Rikers Island is served by Queens but legally in the Bronx, so its BBLs start with 2. Block numbers are unique within a borough and lot numbers are unique within a block.

The Department of Finance points out why the city prefers BBLs to addresses: a property's block and lot don't change when the building moves its entrance to another street, and they can tell apart different condo units in the same building. That is also why a corner building or a large complex can have several street addresses but a single BBL.

Condos: unit lots and billing lots

Condos are the main source of BBL confusion. Each condo unit is its own tax lot, numbered from 1001 to 6999. All the units in a complex share a billing lot, numbered 7501 to 7599. When a condo is first created, the original land lot is replaced; City Planning calls that original the "base lot" or "formerly known as" lot.

• Your own condo's tax bill and deed use your unit lot BBL.
• PLUTO (and so Roofy's building facts) combines all units into one record under the billing lot BBL. A 20-unit condo shows once, with 20 residential units.
• The city's building footprint data keeps both: a BASE_BBL for the lot the building physically sits on, and a MAPPLUTO_BBL that matches the billing lot.

What a BIN is

According to the city's building footprint metadata, a BIN is "a number assigned by City Planning and used by Dept. of Buildings to reference information pertaining to an individual building." The first digit is the borough code (same as in the BBL) and the other six are unique within that borough.

One trap: a BIN of 1000000, 2000000, 3000000, 4000000 or 5000000 means the BIN is unassigned or unknown. These "million BINs" are shared by many unrelated buildings, so never treat one as a real identifier. If a DOB record shows a million BIN, search by address or BBL instead.

A lot with a house and a detached garage, or a housing complex with several buildings, has one BBL and several BINs. PLUTO's "number of buildings" is calculated exactly that way: by counting the BINs in the footprint data that fall on each lot.

Which records use which ID

The practical upshot: to see DOB complaints for a building you need its BIN, while 311 complaints and sales are matched by BBL. On a multi-building lot, a BBL-based record may belong to any of the buildings, and a BIN-based record will name the specific one. Roofy matches these records to each property for you; its building page address ends in the BBL.

How to find the BBL and BIN for an address

1. Roofy: search the address on the building lookup. The page URL ends in the 10-digit BBL, and Building details shows the block and lot.
2. ACRIS: the Department of Finance says ACRIS lets you find a property's BBL from its address (or the reverse). ACRIS covers Manhattan, Queens, the Bronx and Brooklyn records from 1966 on; Staten Island documents are recorded with the Richmond County Clerk instead. See how to search ACRIS.
3. ZoLa: City Planning's zoning map shows the BBL when you click a lot, along with its zoning.
4. Your paperwork: property tax bills, deeds and HPD registration forms all carry the borough, block and lot.
5. BIN: it appears on DOB permits, job filings and violations for the building and in the city's building footprint data. Use the address to find the building's DOB records, then read the BIN from them.

Next steps: look up a building's deeds in ACRIS, decode its permits with how to read DOB permits, or see what the lot data means in PLUTO fields explained.