Once you know the occupancy and construction type, Chapter 5 tells you whether the building is even permitted at its proposed size. Table 504.3 and 504.4 set allowable height in feet and in stories; Table 506.2 sets allowable area — all cross-referenced by construction type and occupancy group.
Two things buy you more: an automatic sprinkler system (a substantial height, story, and area increase) and street frontage (an area increase under 506.3). Mixed-use buildings apply the tables through the separated or nonseparated rules of Section 508, which changes the math.
The common mistake is designing area or stories to the sprinklered increase while the sprinkler requirement itself is still marked "TBD," or declaring a construction type the structural set won't actually deliver. Reviewers re-run the height-and-area math on the code sheet against the declared type, occupancy, and sprinkler status — so those three have to be locked before the area calc means anything.
This guide describes the model code for general understanding and is not a substitute for the adopted code and amendments enforced by your local authority having jurisdiction. Verify all figures against your jurisdiction's codes of record.