Enter a room's length, width, and height to calculate the wall and ceiling area, and how many drywall sheets it takes.
How to Use the Drywall Calculator
Enter the room's length, width, and wall height, then tick the ceiling box if you're rocking that too. Subtract known door and window area in the deduction field, and adjust the sheet size if you're using something other than a standard 4×8 panel.
A rectangular room's wall area is just its perimeter times its height — no diagonal cuts to account for on flat walls, unlike a roof or a driveway.
Wall area = 2 × (Length + Width) × Height
Ceiling area = Length × Width (if included)
Total area = Wall area + Ceiling area − Deductions
Sheets needed = ⌈(Total area × (1 + Waste % ÷ 100)) ÷ Sheet size⌉Standard Sheet Sizes
4×8 ft (32 sq ft) is the panel size most drywall is sold in, and it's this calculator's default. Larger 4×10 and 4×12 sheets cut down on seams for tall or wide walls — change the sheet size field to match whatever your supplier stocks.
Openings Matter More Than They Look
A single door is around 21 square feet and a standard window about 15 — small numbers next to a whole wall's area, but they add up fast in a room with several of each. Leaving the deduction field at zero just rounds your sheet order up a little, which is harmless if a spare half-sheet is useful elsewhere.
Ten Percent Waste Is a Starting Point, Not a Rule
Cuts around outlets, corners, and odd angles chew through more board than a flat wall suggests. Rooms with lots of corners or electrical boxes often run higher than 10%; a plain rectangular room with few openings can sometimes get by on less.