How many drywall sheets do I need for a room?

Find the total wall and ceiling area, subtract openings, then divide by the area of one sheet (32 sq ft for 4×8, 48 sq ft for 4×12) and add about 10 percent for waste. A 12 by 12 foot room with 8 foot walls needs roughly 12 to 14 sheets of 4×8.

How many screws per sheet of drywall?

A common figure is about 32 screws per 4×8 sheet on walls at 16 inch stud spacing — roughly one screw per square foot. Ceilings use a tighter pattern and slightly more. The tool scales screws by total board area at about one per square foot.

How much joint tape do I need?

Tape every seam between sheets plus the inside corners. A rough estimate is about 0.4 linear feet of tape per square foot of board. The tool uses that ratio, so a 500 square foot job needs roughly 200 feet of tape.

How much joint compound for a 3-coat finish?

A standard 3-coat finish (tape coat, fill coat, finish coat) uses roughly 0.06 to 0.07 gallons of ready-mix compound per square foot of board. The tool estimates about one 4.5 gallon bucket per 70 to 75 square feet.

Should I hang the ceiling first?

Yes. Hang the ceiling before the walls so the top wall sheets push up and support the ceiling edges, giving tighter joints. The calculator can include or exclude the ceiling so your sheet count matches your plan.

Drywall Sheet Calculator

Estimating drywall is mostly geometry: add up the wall and ceiling area, take out the openings, and divide by sheet size. This calculator does that and then layers on the consumables — screws, joint tape, and compound — so a single room estimate gives you a complete shopping list for a 3-coat finish.

How it works

Wall area is the room perimeter times the ceiling height; the ceiling adds the floor footprint when included. Openings are deducted, then sheets and consumables follow from total board area:

wall area    = 2 × (length + width) × height
ceiling area = length × width        (if hanging ceiling)
net area     = wall + ceiling − openings
sheets       = ceil(net area × 1.10 / sheet area)
screws       ≈ net area × 1.0   (≈ 1 per sq ft)
tape (ft)    ≈ net area × 0.4
compound gal ≈ net area × 0.066

Each door is treated as about 21 square feet and each window about 12 square feet of deductible opening.

Example and tips

A 12 × 12 ft room with 8 ft walls, one door and one window, ceiling included, has about 384 sq ft of walls plus 144 sq ft of ceiling, less ~33 sq ft of openings — roughly 495 sq ft net. At 4×8 sheets that is about 17 sheets with waste, around 495 screws, 198 ft of tape, and 33 gallons (a couple of buckets) of compound. Buy 5 percent more compound than the math says; the finish coat always uses more than expected.