Space Programming Calculator

The calculator looks up a fixed efficiency percentage for each building type — roughly 82-88% for office and retail, but only 60-65% for healthcare, education, and hospitality — and the Grossing Factor is just 1 divided by that efficiency. Healthcare and hospitality buildings need wider corridors, more restrooms, and heavier mechanical infrastructure, so a smaller share of every gross square foot is usable program space, producing a bigger grossing multiplier.

Usable Area takes your entered net program areas and adds a flat 12% for internal circulation within your own tenant space — hallways between workstations, not building common areas. Gross Area instead multiplies net area by the building type's grossing factor, which captures everything outside the tenant space too, including corridors, restrooms, mechanical rooms, and elevator lobbies, so Gross Area is always the larger of the two figures.

It divides your Private Offices area by 180, Open Office area by 64, and Conference area by 25, then rounds the sum — these are typical square-feet-per-person ratios, not measurements of your actual furniture layout or headcount plan. Support and reception areas aren't included in the occupant estimate at all, so use it as a rough sanity check rather than a staffing count.

They aren't independently modeled — the calculator takes the single Loss Area figure (Gross Area minus Net Area) and splits it by fixed percentages: 35% corridors, 20% mechanical, and 15% each for restrooms, wall thickness, and elevator lobbies. These shares are typical assumptions rather than derived from your specific building type or program mix, so a real floor plan's actual split could differ meaningfully.