Every property in New York City has a permanent identifier that never changes, even when the address does. It is called the BBL, and once you have it you can pull up almost everything the city knows about a building in a couple of minutes.
What BBL stands for
Borough, Block and Lot. Three numbers that together point at exactly one tax lot in the five boroughs.
The borough is a single digit. 1 is Manhattan, 2 is the Bronx, 3 is Brooklyn, 4 is Queens and 5 is Staten Island.
The block is a five digit number identifying a block within that borough. Block numbers repeat across boroughs, which is why the borough digit has to come first.
The lot is a four digit number identifying the individual parcel on that block.
Written out in full it is ten digits. A Brooklyn property on block 1234, lot 56 is 3012340056. You will often see it displayed with dashes or spaces, as 3-01234-0056, but the underlying number is the same.
Why it matters more than the address
Street addresses are unreliable identifiers. A corner building can have two of them. Buildings get renumbered. A single tax lot can contain several addresses, and a large development can span multiple lots.
The BBL does not move. It is the key that city systems use internally, so if you want to search property records, check violations, look up zoning, or file anything with the city, the BBL is what actually gets you there.
Note one exception: a condominium unit usually has its own unit lot number, distinct from the building lot, and lot numbers in the 1000s or higher often signal a condo unit rather than a whole parcel.
A wrong borough, block or lot gets a deed rejected at recording. We notarize and file through ACRIS with the transfer tax forms, from intake to confirmation.
Four ways to find a BBL
The city’s BBL lookup. The simplest route is nyc.gov/bbl, where you enter a borough and street address and it returns the borough, block and lot.
Your property tax bill. If you own the property, the BBL is printed on the Department of Finance statement, usually near the top with the account information.
ZoLa, the Zoning and Land Use map. Click any lot on the map and the panel shows the BBL along with the zoning district. See how to use ZoLa.
ACRIS. Search by address in the property records system and the BBL appears with the document list. See the ACRIS guide.
Staten Island is the one to watch. Property records for Richmond County are held by the Richmond County Clerk rather than in ACRIS, even though the BBL system still applies.
What you can do once you have it
Pull the deed and the ownership history. ACRIS holds recorded deeds, mortgages, satisfactions, liens and assignments by BBL. See how to find a property owner.
Check housing violations. HPD Online lists open and closed violations, complaints and registration status by address or BBL. See HPD Online.
Check construction and building records. The Department of Buildings information system holds permits, jobs, complaints and DOB violations.
Check zoning. ZoLa shows the district, overlays and special districts governing what can be built.
Check taxes and exemptions. Department of Finance records show assessed value, tax class, exemptions such as STAR, and any outstanding charges.
Check the tax map. The Digital Tax Map shows the lot’s shape and dimensions and its relationship to neighbouring lots.
When you will actually need it
Recording a deed or mortgage. Filing transfer tax forms, since the BBL appears on both the TP-584 and the RP-5217. Ordering a title search. Researching a property before you buy. Confirming who owns a building you are dealing with. Responding to a violation. Verifying that a property in an estate is the one described in the will.
It also matters for deed recording. A wrong BBL on a filing means a rejected submission, and the correction costs you days.
Common mistakes
Dropping leading zeros. Block and lot fields are padded, so lot 56 is 0056, and software that strips the zeros will send you to the wrong parcel.
Using a neighbouring lot. Corner properties and merged lots are easy to misread on a map. Confirm against the address and the owner name before relying on it.
Assuming a condo unit uses the building lot. It usually does not.
Assuming Staten Island records live in ACRIS. They do not.
Frequently asked questions
Is the BBL the same as a tax lot number?
The lot portion is the tax lot. The full BBL adds the borough and block so the number is unique citywide.
Does a BBL ever change?
Rarely, but yes. Lots can be merged or subdivided, and condominium conversions create new unit lots. The old number is retired.
Can I find the owner from the BBL for free?
Yes. ACRIS and Department of Finance records are public and free to search.
Do I need the BBL to record a deed?
Yes. It identifies the property on the recording and on the transfer tax forms.
What about Staten Island?
The BBL applies, but recorded documents are searched through the Richmond County Clerk.
Reading a BBL on a document
You will meet the number in several formats and they all mean the same thing. A deed might show it as three separate fields labelled Borough, Block and Lot. ACRIS displays it that way too. Software and datasets usually concatenate it into ten digits, and some sources insert dashes for readability.
What never changes is the padding. The block is always five digits and the lot always four, so Brooklyn block 1234 lot 56 is 3 01234 0056. If a system hands you 3123456 with the zeros stripped, that number is unusable and you need to re-pad it before searching.
Condominium units
Condominiums are the most common source of confusion. The building sits on one tax lot, and each unit is assigned its own unit lot number, usually in the 1000s or higher on the same block.
So a search using the building lot returns the building record and not your apartment, and a search using the unit lot returns your apartment and not the common elements. If you own a condo, the lot number on your tax bill is the one that identifies your unit, and it is the one that belongs on a deed or a filing.
When lots change
Lots are occasionally merged, subdivided or reassigned, and a condominium conversion creates a whole set of new unit lots. When that happens the old number is retired.
That matters for historical searches. A document recorded before a merger sits under the old number, so if a chain of title appears to stop abruptly, the lot may simply have been renumbered rather than the record being missing. The Digital Tax Map and the ACRIS document history are where you trace that.
Related reading
- ACRIS: searching property records and recording a deed
- How to find a property owner in NYC
- ZoLa: the zoning and land use map
- HPD Online: violations and registration
- NYC deed and document recording
This is general information, not legal advice. City systems and their addresses change, so confirm details with the relevant agency before relying on them for a filing.