MEASURE. ESTIMATE. BUILD.
Count the Sheetrock panels for your room.
Change any measurement to update your estimate.
Sheetrock is a drywall brand; this tool counts 4×8 sheets (32 ft² each) with a 10% waste allowance.
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.
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.
The math behind the tool:
sheets = total area ft² ÷ 32 × (1 + waste%)Sources: Gypsum Association (gypsum board sizes and finishing).
Divide your total wall and ceiling area by 32 ft² (the coverage of a 4×8 sheet), then add about 10% for waste. A 12×12 room with 8 ft walls needs roughly 14 sheets.
Plan on about 0.053 lb of ready-mix joint compound per square foot of drywall for taping and three coats — roughly one 4.5-gallon box per 12 sheets.