BIN and BBL: the two numbers NYC systems actually use
Last reviewed Oct 6, 2026 · NYC property compliance guides
A BIN identifies one building. A BBL identifies one tax lot, which may hold several buildings. City systems key records to one or both, so searching by address alone can return records for a neighbouring building or miss records entirely.
The two identifiers
- BIN — Building Identification Number
- Seven digits, where the first digit is the borough: 1 Manhattan, 2 Bronx, 3 Brooklyn, 4 Queens, 5 Staten Island. It identifies a single building. DOB records are generally keyed to it.
- BBL — Borough, Block and Lot
- Ten digits: one borough digit, a five-digit block and a four-digit lot. It identifies a tax lot. Property tax, zoning and ownership records use it, and a lot can contain many buildings.
Why this causes real mistakes
A large development can sit on one BBL with a dozen BINs. Searching the BBL returns everything on the lot, including buildings you do not manage. Searching one BIN returns a single building and silently omits the rest.
The reverse error is more dangerous. Somebody checks an address, sees a clean record, and concludes the property is clear — when the system matched a different BIN on the same lot. Nothing warns you, because from the system’s point of view the search succeeded.
Corner buildings add their own version: two legal addresses on two streets, and records distributed between them depending on which one the inspector wrote down.
Finding the BIN and BBL for a building
Search the address in DOB BIS
The property profile shows the BIN at the top, along with the block and lot. If several buildings are returned, each will have its own BIN.
Confirm on the city zoning map
ZOLA shows the lot outline and the buildings on it, which is the quickest way to see whether the address you have covers one building or several.
Record both, not one
Keep the BIN and the BBL with the property record. Different agencies will ask for different ones, and reconstructing them later under time pressure is how the wrong building gets checked.
Common questions
Can one building have more than one BIN?
It should not, but data errors exist, and buildings that have been merged, subdivided or rebuilt sometimes carry historical identifiers. If two BINs return overlapping records for what is plainly one building, check both.
Is the BBL the same as the tax lot on my bill?
Yes. The borough, block and lot on a property tax bill are the components of the BBL, usually written separately rather than as a single ten-digit string.
Which should I use to search for violations?
Use the BIN where a system accepts it, because it identifies the building unambiguously. Use the BBL when you want everything on the lot, which is usually the right choice in due diligence.
Official sources
Rules and figures change. Check anything you are about to act on against the agency itself.
Related guides
- How to check violations on a NYC property
Check HPD, DOB, ECB/OATH, 311, DEP and FDNY records for any New York City building, with the official lookup for each and what every system does not show.
- How to check DOB violations by address
Look up Department of Buildings violations for any NYC address using the BIS property profile, and understand why DOB violations and ECB summonses are listed separately.
- Buying a NYC building with open violations
Open violations transfer with the building, not the seller. What to search before you commit, which records matter most, and what tends to be negotiated.
- HPD violation lookup: finding housing violations by address
How to look up HPD violations for a NYC building, how to read the class, status and certification dates, and why HPD Online and Open Data can disagree.
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