Sheetrock is a brand of gypsum board. Coverage is still panel length times width. 4×8 panels are 32 sq ft, 4×10 are 40, 4×12 are 48—longer sheets can mean fewer seams on tall walls.
Enter wall area and ceiling area apart so you can hang ceilings with a different thickness (often 5/8 in) while walls stay 1/2 in. Waste still applies to the combined area for a single shopping list, or run the tool twice for two SKUs.
Screw counts of roughly 32–38 per 4×8 sheet are a planning figure, not a framing-code schedule.
Generic gypsum counts are on the drywall calculator. Once the room is closed, size cooling from the same footage with the AC ton calculator.
How this calculation works
Same area math as drywall: ceil((walls + ceiling) × (1 + waste) ÷ panel sq ft).