Room number

A room number is a number assigned to a room within a building. Its purpose is to identify a particular room, and help visitors locate that room. Room numbers may consist of three digits, but can be any number of digits.

The room number is generally assigned with the first digit indicating the floor on which the room is located. For example, room 412 would be on the fourth floor of the building; room 540 would be on the fifth floor. Buildings that have more than ten floors will have four digits assigned to rooms beyond the ninth floor. For example, room 1412 would be on the 14th floor.

The second digit may represent the wing, or section, of the building in which the room is located: room 540 will typically be found adjacent to room 542, and room 532 adjacent to room 530. In a four digit room number, this digit will be the third digit instead of the second.

The third digit is then assigned based on the side of the hall on which the room is located: usually, one side of the hall has odd-numbered rooms and the opposite side has even-numbered rooms. In a four digit room numbers, this digit will be represented by the fourth digit instead of the third. Where a room is subdivided, the subdivisions are generally denoted by appending a letter suffix to the room number: for example, room 412 may be subdivided into rooms 412A and 412B.

A letter may appear before the numbers to indicate a particular building or wing. For example, Room D149 is a room in D building and is not a hypothetical example.

Apartment Numbers

Some apartments are numbered using the regular room number assignment method, where apartment 1412 will be on the fourteenth floor. Most apartments, however, are assigned with a number followed by a letter. There may be one or two numbers in the apartment number, followed by just one letter. For example, apartment 14R would be on the fourteenth floor. Apartment 7B would be on the seventh floor.