I had created a free online calculator to determine allowable heights, number of stories, and floor area, based on various criteria in the International Building Code (IBC). This calculator, however, was getting old and out of date, so I finally revised it, based on the 2021 and 2024 IBC (the latest iterations currently available). It’s free and (relatively) easy to use, so try it out, here.

Generic site plan showing various parameters for the calculation of the area increase factor (for frontage).