Drywall Calculator
Use this drywall calculator to work out how many sheets of drywall a room needs and how much joint compound, tape and screws to buy. Enter the room length, width and height, subtract doors and windows, optionally add the ceiling, then pick a sheet size and a waste percentage. Finishing quantities are typical figures from USG and National Gypsum guidance and you can adjust them. For paint after drywall, use the paint calculator; for floor area, the square footage calculator.
Math runs in your browser. Nothing is uploaded.
Finishing materials per 1,000 sq ft of board (typical, adjustable)
Wall area
—
Ceiling area
—
Doors and windows
—
Net area to cover
—
Sheets before waste
—
Sheets to buy (with waste)
—
Joint compound needed
—
4.5 gal pails (rounded up)
—
Joint tape needed
—
Tape rolls (rounded up)
—
Screws needed
—
Estimated cost
—
Wall area = perimeter × height, plus length × width if the ceiling is included. Net area = walls + ceiling − doors and windows. Sheets = net area × (1 + waste) ÷ sheet area, rounded up. Compound, tape and screws use the net area without waste and the typical rates per 1,000 sq ft of board: about 10 gal of ready-mixed all-purpose compound (USG Sheetrock product data), and 350 ft of tape and 768 screws (National Gypsum ProForm estimating table). Finish level, framing spacing and product change them, so edit the rates. The 21 sq ft door (3 × 7 ft) and 15 sq ft window are adjustable placeholders. Follow the board maker's fastening rules and your local code.
Paint Calculator · Square Footage Calculator · Lumber Calculator · Tile Calculator · Insulation Calculator · Wallpaper Calculator
More in this group
How it works
- How many sheets of drywall do I need for a room?
- Add the wall area (perimeter × height) and the ceiling if you are boarding it, subtract doors and windows, add waste, and divide by the sheet area. A 12 ft × 14 ft room with 8 ft walls has 416 sq ft of wall. Minus one 21 sq ft door and two 15 sq ft windows leaves 365 sq ft, and 365 × 1.1 ÷ 32 = 12.5, so 13 sheets of 4 × 8 ft.
- What size are drywall sheets?
- Sheets are 4 ft wide, and National Gypsum's estimating table lists 8, 10 and 12 ft lengths, which cover 32, 40 and 48 sq ft. Where metric sizes are used, 1.2 × 2.4 m (2.88 m²) is a common size. Choose the size you will actually buy, because it changes the sheet count.
- How much joint compound do I need?
- USG lists about 10 gal of Sheetrock all-purpose ready-mixed compound per 1,000 sq ft of gypsum panels, which is about 1 gal per 100 sq ft and roughly one 4.5 gal pail per 450 sq ft. The 365 sq ft room above needs about 3.7 gal, so one pail. Finish level, texture and the product change the amount, so check the label.
- How much drywall tape and how many screws do I need?
- National Gypsum's ProForm estimating table gives 350 ft of joint tape and 768 screws per 1,000 sq ft of board. For 365 sq ft that is about 128 ft of tape, one 250 ft roll, and 281 screws. Screw spacing comes from the board maker's instructions and local code, so treat these as starting figures.
- How much waste should I add?
- The default is 10%, an adjustable allowance for cuts, offcuts and damaged edges rather than a standard value. A simple room with few openings may need less, and a room with many angles or odd cuts may need more. Compound, tape and screws are calculated on the net area without waste.