What Is a BBL? NYC Borough-Block-Lot Explained
A BBL is NYC's 10-digit Borough-Block-Lot tax lot ID: 1 borough digit, 5 block, 4 lot. Borough codes, zero-padding, lot ranges, and how to look one up.
Quick answer
A BBL is the 10-digit Borough-Block-Lot number that identifies every tax lot in New York City: one borough digit (1 Manhattan, 2 Bronx, 3 Brooklyn, 4 Queens, 5 Staten Island), a five-digit tax block, and a four-digit tax lot, each zero-padded. The Empire State Building is BBL 1008350041: borough 1, block 835, lot 41.
What is a BBL?
The BBL is the primary key of New York City real property. The Department of Finance assigns it, the Department of City Planning publishes it, and the datasets a title search actually reads are all keyed to it: ACRIS, PLUTO, the Digital Tax Map, DOB and HPD.
The NYC Zoning Tax Lot Database states the format directly: "The borough code is one numeric digit. The tax block is one to five numeric digits, preceded with leading zeros when the block is less than five digits. The tax lot is one to four digits and is preceded with leading zeros when the lot is less than four digits."
A tax lot is not a building and it is not an address. It is a parcel as drawn on the Department of Finance tax map. One lot can carry several buildings, several street addresses, or, in the case of an air rights lot, no ground at all.
Definition
BBL (Borough-Block-Lot) — A BBL is the 10-digit numeric identifier New York City assigns to every tax lot. It is one borough digit, then a five-digit tax block, then a four-digit tax lot, with leading zeros added so the value is always exactly 10 characters.
What are the NYC borough codes?
The borough digit is numeric only inside the BBL. In PLUTO the standalone borough field is a two-character alphabetic code instead: MN, BX, BK, QN, SI. Code that assumes one representation and receives the other joins to nothing, which is a routine cause of empty result sets when combining PLUTO with ACRIS or DOB data.
| Digit | Borough | County | Where deeds are recorded |
|---|---|---|---|
| 1 | Manhattan | New York County | Office of the City Register (ACRIS) |
| 2 | Bronx | Bronx County | Office of the City Register (ACRIS) |
| 3 | Brooklyn | Kings County | Office of the City Register (ACRIS) |
| 4 | Queens | Queens County | Office of the City Register (ACRIS) |
| 5 | Staten Island | Richmond County | Richmond County Clerk |
How do the ten digits fit together?
The Empire State Building is a useful worked example because its BBL can be checked against three independent city sources.
Take the borough digit
The building is in Manhattan, so the first digit is 1.
Pad the block to five digits
The tax block is 835. Written to five digits it becomes 00835.
Pad the lot to four digits
The tax lot is 41. Written to four digits it becomes 0041.
Concatenate without separators
1 + 00835 + 0041 gives 1008350041. NYC Planning GeoSearch returns this BBL for 350 5 Avenue; PLUTO records the owner of BBL 1008350041 as ESRT EMPIRE STATE BUILDING, L.L.C., 102 floors, built 1931; and ACRIS indexes documents to borough 1, block 835, lot 41. Three sources, one identifier.
Why does zero-padding break BBL lookups?
Zero-padding is where most BBL lookups quietly fail. The concatenated 10-digit BBL is always padded. The separate borough, block and lot columns inside city datasets are not padded consistently, and an exact-match query against the wrong form returns an empty set rather than an error.
Three NYC Open Data datasets describe the same Empire State Building parcel three different ways. ACRIS Real Property Legals stores borough "1", block "835", lot "41". DOB Violations stores boro "1", block "00835", lot "00041". PLUTO stores borough "MN", block "835", lot "41", and returns the BBL itself as the decimal string "1008350041.00000000".
The failure is silent. Querying DOB Violations for Manhattan block 835 returns zero rows. The identical query for block 00835 returns more than a thousand. Nothing warns you that you asked the wrong question, and a report generated from the first query simply has no violations section.
Padding is not even consistent within a single dataset. On Manhattan block 00835, DOB Violations stores lot 41 as both 00041 and 0041. Queried on 18 August 2026, an exact match on 00041 returned 687 records and an exact match on 0041 returned 2. A search that tests only one form drops the other.
The durable fix is to normalize on read rather than to memorize each dataset. Cast borough, block and lot to integers at ingest, then re-pad to 1, 5 and 4 digits only when you need to emit a BBL string. Never compare a padded string to an unpadded one, and never let a BBL pass through a floating-point type.
What do lot numbers in the 1000s, 7500s, 8000s and 9000s mean?
Lot numbers are not arbitrary. The Department of Finance reserves numeric ranges for lots that represent a legal interest rather than a piece of ground. Recognizing the range tells you what kind of thing you are searching before you read a single document.
These ranges classify; they do not validate. The Department of Finance publishes this caveat in its own Digital Tax Map metadata: "Although DOF has a set of defined limits for different types of lots, the fact that there are exceptions to these rules makes it impossible to use a domain for validity checking of the lot numbers." A pipeline that rejects a lot number for falling outside the expected band will reject real parcels.
The 7500s matter more than the rest. The Department of City Planning describes the mechanic plainly: if a residential condominium contains 20 units, Finance assigns 20 unit lot numbers, and all 20 share a single billing lot number. The Digital Tax Map additionally carries the condominium base lot, which DOF calls the "Formerly Known As" or FKA lot, the number the parcel held before the condominium declaration was recorded.
Encumbrances recorded against the sponsor before the declaration, or against the building as a whole afterward, sit on the base lot and the billing lot. They do not encumber the individual unit lot a buyer is acquiring. A search that sweeps every lot on the block and reports the result as the unit's title will show a condo purchaser a stack of mortgages that have nothing to do with the unit. That is the most common false positive in cheap NYC title data, and it is worked through in detail in condo master lot vs unit lot.
| Lot range | What it represents | Documented in |
|---|---|---|
| 1 to 999 (typical) | An ordinary tax lot: a physical parcel with a boundary on the tax map. | DOF Digital Tax Map |
| 1001 to 6999 | Condominium unit lots. Each condo unit is its own tax lot with its own lot number. | DCP PLUTO Data Dictionary |
| 7501 to 7599 | Condominium billing lots, commonly called the master lot. Every unit in a complex on the same block shares one billing lot number. | DCP PLUTO Data Dictionary |
| 8000 to 8999 | Subterranean rights lots. | DOF Digital Tax Map: Subterranean Lots |
| 9000 to 9989 | Air rights lots. | DOF Digital Tax Map: Air Lots |
How do I find a property's BBL?
Four official routes, in the order most practitioners should try them.
NYC Planning GeoSearch, for programmatic lookup
The Department of City Planning runs a free geocoder at geosearch.planninglabs.nyc that takes an address string and returns the BBL, with no API key required. It is the cleanest address-to-BBL path for software and is documented here.
DOF Property Information Portal, for the authoritative tax map
propertyinformationportal.nyc.gov is the Department of Finance tax map viewer. It shows the lot boundary and annotations for associated condominium, air, subterranean and REUC lots, and it exposes the Digital Alteration Book, the official log of lot merges, splits and boundary changes.
ACRIS, when you are going straight to documents
a836-acris.nyc.gov/CP searches recorded property documents by borough, block and lot, or by address when you still need to resolve the block and lot. This is the index a NYC title search reads.
PLUTO or MapPLUTO, for bulk work
PLUTO carries one record per tax lot with the BBL precomputed, plus lot area, building class, year built and unit counts. Use it when you need BBLs for a whole block, neighborhood or portfolio rather than a single parcel.
Why is BBL, not the address, the correct key for a title search?
An address is a label people type. A BBL is the identifier the recording system indexes on. Searching by address means searching for a spelling.
The Empire State Building shows how far apart those two things drift. Queried on 18 August 2026, the ACRIS Real Property Legals dataset indexed documents to BBL 1008350041 under nine distinct address strings, plus records with the address field left blank. The nine were 350 FIFTH AVENUE, 350 FIFTH AVE, 350 5 AVENUE, 350 5TH AVENUE, 338 5 AVENUE, 336 5 AVENUE, 338-350 FIFTH AVENUE, 338-50 FIFTH AVE, and 33 W 33RD ST. PLUTO gives the same lot's primary address as 338 5 AVENUE. Every one of those is one tax lot.
Search that lot by address string and you are guessing which spelling a given instrument used, and you will miss the documents recorded from the West 33rd Street side entirely. Search it by BBL and you get every document ACRIS has indexed to the parcel regardless of how the address was typed.
This is why a lender or an attorney asks for block and lot rather than an address, and why HeritageDeed keys every NYC report to a BBL. Address matching is used to find the BBL; it is never used to run the search.
One boundary is worth stating plainly here, because the Department of Finance states it about its own records: "Reviewing these documents is not necessarily the same as a title search." The same logic extends one step further. HeritageDeed runs BBL-keyed searches of public records and returns a report as PDF and structured JSON, priced at $49, $79 and $129. It does not sell or underwrite title insurance. A mortgaged purchase closes on a policy issued by an insurer, and no search product substitutes for that — the two are compared in title search vs title insurance.
What BBL edge cases catch professionals out?
- Marble Hill and Rikers Island. The Department of City Planning notes that Marble Hill is serviced by the Bronx but legally located in Manhattan, and that Rikers Island is serviced by Queens but legally located in the Bronx. PLUTO assigns the borough of legal location, so Marble Hill BBLs begin with 1 and Rikers Island BBLs begin with 2.
- Staten Island recording. The Office of the City Register records property documents for the Bronx, Brooklyn, Manhattan and Queens, and the Department of Finance directs users to the Richmond County Clerk for Staten Island property. A Staten Island BBL is perfectly valid, but an ACRIS-only workflow will not see everything a Richmond County parcel carries.
- The 1966 floor. DOF states that ACRIS provides online access to property documents and data dating back to 1966, and directs users to the Land Records Research Library at the Queens City Register Office for anything earlier. A clean ACRIS result for a BBL is not evidence of a clean chain before 1966.
- BBLs are not permanent. Lots merge, split and get renumbered, and a condominium declaration creates an entirely new lot series on the block. DOF logs these changes in the Digital Alteration Book, published through the Property Information Portal. A BBL copied from an older report may no longer describe the parcel in front of you.
- A BBL is not a BIN. The Building Identification Number identifies a structure; the BBL identifies the land. One tax lot can hold many BINs, which is why DOB records frequently need both.
Key takeaways
Key takeaways
- A BBL is exactly 10 digits: 1 borough digit, 5 block digits, 4 lot digits, zero-padded.
- Borough codes are 1 Manhattan, 2 Bronx, 3 Brooklyn, 4 Queens, 5 Staten Island. PLUTO uses MN, BX, BK, QN, SI for the same field.
- The Empire State Building is BBL 1008350041: borough 1, block 835, lot 41.
- Condo unit lots run 1001 to 6999, condo billing lots 7501 to 7599, subterranean lots 8000 to 8999, air rights lots 9000 to 9989. DOF warns that exceptions exist, so classify on these ranges rather than validating on them.
- Zero-padding is inconsistent across NYC datasets and sometimes within a single dataset. Normalize to integers on read and re-pad only on output.
- One tax lot can carry nine or more address spellings. Search by BBL; use the address only to find it.
Frequently asked questions
- How many digits is a NYC BBL?
- A NYC BBL is exactly 10 digits: one borough digit, five tax block digits, and four tax lot digits. Blocks and lots shorter than their field width are padded with leading zeros, so block 835 becomes 00835 and lot 41 becomes 0041.
- What are the NYC borough codes in a BBL?
- 1 is Manhattan, 2 is the Bronx, 3 is Brooklyn, 4 is Queens, and 5 is Staten Island. These codes are published by the Department of City Planning in the NYC Zoning Tax Lot Database and are used consistently across ACRIS, DOB, HPD and the Digital Tax Map.
- What is the BBL for the Empire State Building?
- The Empire State Building is BBL 1008350041, which is borough 1 (Manhattan), block 835, lot 41. NYC Planning GeoSearch returns this BBL for 350 5 Avenue, and PLUTO lists the owner of that BBL as ESRT EMPIRE STATE BUILDING, L.L.C.
- Why does my BBL lookup return no results?
- Almost always zero-padding. Some NYC datasets store block and lot padded, such as DOB Violations using 00835 and 00041, while others store them unpadded, such as ACRIS using 835 and 41. An exact-match query in the wrong format returns an empty set with no error. Normalize to integers, then re-pad.
- What does a lot number in the 7500s mean?
- A lot number between 7501 and 7599 is a condominium billing lot, often called the master lot. Every unit in a condominium complex on the same block shares that billing lot number. Individual condominium unit lots are numbered 1001 to 6999.
- Is a BBL the same as block and lot?
- A BBL is block and lot with the borough digit prepended and both fields zero-padded to fixed width. Block and lot alone are ambiguous citywide because block numbers repeat in every borough; a tax block is unique only within its borough.
- Can I search a Staten Island property by BBL in ACRIS?
- Staten Island BBLs are valid and begin with 5, but the Office of the City Register records documents for the Bronx, Brooklyn, Manhattan and Queens only. The Department of Finance directs users to the Richmond County Clerk for Staten Island property, so an ACRIS-only search of a Richmond County parcel can be incomplete.
- Does a BBL search give me title insurance?
- No. A BBL search reads public records and reports what is indexed against a parcel. Title insurance is a policy underwritten by an insurer. HeritageDeed produces searches and structured reports and does not sell or underwrite title insurance; closing a mortgaged purchase requires a policy from an insurer.
Sources
Primary records and official documentation cited in this article.
- 1NYC Zoning Tax Lot Database (BBL format and borough codes) - NYC Open Data
- 2PLUTO Data Dictionary, May 2026 (26v1) - NYC Department of City Planning
- 3Recording Property-Related Documents - NYC Department of Finance
- 4Digital Tax Map: Air Lots (air rights lot numbers 9000-9989) - NYC Open Data
- 5Digital Tax Map: Subterranean Lots (lot numbers 8000-8999) - NYC Open Data
- 6ACRIS Property Records Search - NYC Department of Finance
- 7ACRIS Real Property Legals (dataset behind the address-spelling counts above) - NYC Open Data
- 8DOB Violations (dataset behind the zero-padding counts above) - NYC Open Data
- 9NYC Planning GeoSearch API documentation - NYC Department of City Planning
- 10NYC Property Information Portal (tax map viewer and Digital Alteration Book) - NYC Department of Finance
HeritageDeed provides public-record search reports only. Reports do not constitute title insurance, an attorney opinion of title, or a title insurance commitment.