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Drywall Calculator

Count drywall sheets, screws, tape and joint compound for walls and ceilings — sized for 4×8 and 4×12 sheets.

Drywall Calculator

Sheets of drywall, joint compound, tape and screws for walls and ceilings.

How this is calculated

Area = (perimeter × height + optional ceiling) × rooms − openings (door ≈ 21 ft², window ≈ 15 ft²). Sheets = area × (1 + waste) ÷ sheet area, rounded up. Compound ≈ 1 gal per 100 ft²; tape ≈ 0.37 ft per ft².

Enter the room size and number of door and window openings, choose your sheet size and thickness, and get the number of sheets, joint compound, tape, screws, total weight and cost.

Results are estimates for planning purposes only. Real-world quantities depend on site conditions, materials and workmanship. Always verify measurements, follow local building codes and confirm quantities with your supplier or a qualified professional before ordering or building.

About the Drywall Calculator

Drywall is sold by the sheet, so guessing wrong means a second trip to the supplier or a stack of sheets you will never use. This calculator turns room dimensions into a full materials list: 4×8 or 4×12 sheets for walls and ceilings, plus screws, joint tape and joint compound. It suits basement finishes, additions and single-room re-drywall jobs alike.

How to use

  1. Enter the room length, width and ceiling height. For multiple rooms, run each separately and add the sheet counts.
  2. Choose whether to include the ceiling — ceilings take different sheet lengths and are calculated separately.
  3. Pick your sheet size: 4×8 for small rooms and easy handling, 4×12 for long walls with fewer seams.
  4. Enter the number of doors and windows so their area is subtracted from the wall total.
  5. Set waste to 10 percent for rooms with many corners, or 5 percent for simple rectangles.

Understanding your results

The sheet count is the number of full sheets to buy, rounded up, with walls and ceilings shown separately since they often use different thicknesses. The screw count covers hanging on 16-inch stud spacing, compound is in 5-gallon buckets, and tape is in rolls of standard 2-inch joint tape.

How the calculation works

Wall area is the room perimeter times ceiling height, minus about 21 square feet per door and 15 per window. That area is divided by 32 square feet per 4×8 sheet (48 per 4×12), waste is added, and the result rounds up. Screws run about 30 per 4×8 sheet, and one 5-gallon bucket of compound tapes and finishes roughly 400 to 500 square feet of drywall.

Drywall Calculator FAQs

About 17 to 19 sheets. The walls are 48 linear feet times 8 feet equals 384 square feet, which is 12 sheets of 4×8. The ceiling is 144 square feet, or 5 sheets. That totals 17 sheets before waste — add 10 percent for cuts and mistakes and you land at 19. Buy the extra sheets; partial sheets at the supplier cost nearly as much.
Use 1/2-inch for most walls — it is the standard residential thickness. Use 5/8-inch on ceilings to resist sagging between joists, and wherever fire code requires it, such as garage ceilings under living space. The 5/8-inch board is heavier and harder to hang solo, so get help on ceiling work.
Plan on about 28 to 32 screws per 4×8 sheet on standard 16-inch stud spacing: screws every 16 inches along each stud, plus along the top and bottom plates. A 25 lb box holds roughly 1,500 coarse-thread screws, enough for about 45 to 50 sheets. For metal studs, use fine-thread screws instead.
A 5-gallon bucket of joint compound tapes and finishes roughly 400 to 500 square feet of drywall through all three coats. A single 12×12 room with about 530 square feet of drywall needs roughly one and a half buckets — buy two, since running out mid-coat is worse than having leftover. Premixed all-purpose compound is the easiest choice for DIY work.
Paper tape is stronger and the pro standard for flat seams and inside corners, but it takes practice to bed without bubbles. Self-adhesive mesh tape is easier for beginners on flat seams, though it should not be used on inside corners and it requires setting-type compound, not premixed, to reach full strength.
Nabil Sharif, founder of CalcDune

Written by

Nabil Sharif

Founder of CalcDune — a free library of 137 online calculators for finance, health and everyday math. Every calculator shows the formula behind its result, so you can see exactly how your numbers are worked out.

More articles by Nabil →

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