Drywall Calculator
Estimate drywall sheets from room size, ceiling option, doors and windows, and 4×8, 4×10, or 4×12 ft US sheet sizes, including waste.
How to use this drywall calculator
US drywall is 4 ft wide. 4×8 sheets are the home-center default; 4×10 and 4×12 reduce butt joints on 9–10 ft walls if you can carry them. Hang ceilings first. This drywall calculator subtracts typical door and window openings so you do not over-order as badly.
Waste covers cutoffs, damaged boards, and a spare. Joint compound, tape, and screws are extra. Fire-rated or moisture-resistant board is a different SKU — count those rooms separately if only the bath gets green board.
Formula
Worked example
A 16×12 room, 8 ft walls, ceiling on, two doors and two windows: walls 448 + ceiling 192 − 70 = 570 sq ft. 4×8 sheets are 32 sq ft → 18 sheets, 10% waste → 20 sheets.
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Frequently asked questions
How many drywall sheets for a 12×12 room?
Walls of an 8 ft 12×12 are 384 sq ft. Ceiling adds 144. Minus openings, then divide by 32 for 4×8 sheets and add 10%.
4×8 vs 4×12 drywall?
4×8 is easier to move. 4×12 can cut seams on taller walls if you can carry them. Pick what fits the truck and the stair.
Do I drywall the ceiling?
Usually yes on a full room. Toggle Include ceiling off for a garage or a wall-only patch.
How much waste for drywall?
10% is standard. Tight rooms with lots of windows may need less because openings already removed area; vaulted ceilings need more.
Does this include mud and tape?
No. Plan joint compound and fasteners from the sheet count, not this area number.
Results are estimates for informational purposes and are not financial, legal, or professional advice. Last reviewed 2026-08-19.