Floor numbers in buildings are usually written as "4th Fl.", or more commonly just "4F," before or after the building name. Room numbers are also sometimes used.

In cases where there is no building name, or it is not commonly used or known, room/office numbers are usually added as an extra (usually 4th) number after the building number; thus, 1-3-4-222 Shinjuku would refer to can be assumed to designate Room or Office number 222, which would probably be on the second floor.

NOTE: Japan follows the US-style floor numbering convention, i.e., the street-level floor is not "Ground (as in Europe) but rather "1st Floor."