The height from the floorplate to structural ceiling, or indoor clearance height, is the maximum consistently open height of a building's interior space, taken at a median-height floor, when intrusions such as mechanical equipment, wiring, lowered ceilings, and raised floors, are not considered. In other words, it is the maximum structurally allowed floor-to-ceiling height when nothing which is not structural gets in the way.

Three fields measure the same story and give three descending numbers. Floorplate to floorplate is the full story including the slab, floor to ceiling is what is left inside the finished room, and the indoor clearance is what remains once ducts and lighting hang below it. A value in the wrong field is out by the thickness of a slab or a ceiling void.

A building rarely has one value throughout. The lobby and the mechanical levels differ from the typical office story, and this field describes the typical one unless the record says otherwise.