Sheetrock is just a drywall brand; the count is the same 4×8 sheets at 32 ft² each. This view applies a 10% waste factor because the offcut from around a door rarely fits anywhere else.
Field notes
Hang the ceiling first, then let the wall sheets support its edges — it's the difference between a job that holds and one that cracks along the top. Order 10% over: the offcut from around a door is rarely reusable elsewhere. For mud, the rule of thumb is one 4.5-gallon box per 12 sheets across tape and three coats, but skim-coat finishes burn through noticeably more.
How the sheetrock calculator works
The math behind the tool:
sheets = total area ft² ÷ 32 × (1 + waste%)Sources: Gypsum Association (gypsum board sizes and finishing).