Key:addr:unit
 addr:unit
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| Description |
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A number, letter or other identifier for a distinct part inside an addressed building or site, such as a building or wing, staircase or entrance group, floor, apartment, suite, office or room  
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| Group: addresses |
| Used on these elements |
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| See also |
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Status: approved
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| Tools for this tag |
addr:unit is a number, letter or another identifier for a distinct part inside an addressed building or site, such as a building or wing, staircase or entrance group, apartment, suite, office or room. A single value may hold several parts together as written locally, e.g. addr:unit=2B, addr:unit=Bldg A Suite 100, but the practice varies regionally. addr:door=* is sometimes used instead of addr:unit=* to specify the unit identifier of an individual apartment, suite, or room.
How to map
Tag the unit on the object it identifies, typically a building or an entrance node. If the object contains multiple units that cannot be mapped individually, but can be specified as a range, use addr:flats=* instead, as in some locales addresses may contain a hyphen to identify a single unit and not a range.
If a building or landuse is tagged with addr:housenumber=* and addr:street=*, then any unit fully within that building or landuse could be spatially inferred to inherit those values to complete their address, and thus may not need to be explicitly tagged with those values. Follow regional practice to determine whether or not this is to be done.
In the United States, there is no consensus on how to represent secondary unit designators, however according to Taginfo it is far more popular to omit the designator and only include the identifier; there are only 2273 "Apartment A/Unit A/Suite A" entries versus 78 613 "A" entries as of September 2026. This practice only allows data consumers to format the unit as "#A", which the USPS says will result in rejected mail in some cases. [1] Consider using addr:full=* to disambiguate.
Rendering
- OpenStreetMap Carto renders
addr:housenumber=*as an overlay label starting from z17, and rendersaddr:housenumber=*together withaddr:unitseparated by a space from z18 onwards. - Nominatim does not currently evaluate
addr:unit(issue 587). - As of September 2026, CoMaps does not yet render a label for
addr:unit, but is looking to implement it.
External discussion
- Secondary address unit designators — forum discussion (from 2025-10-09) on tagging the designator word vs. the identifier in
addr:unit.