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Drywall Calculator

Drywall sheets for a room's walls and ceiling, with the screws, joint tape and compound to finish them.

Updated · By Niraj Kumar

How the Drywall Calculator works

Add up the wall area and the ceiling, take out the doors, and divide by the area of one sheet: 32 sq ft for 4 × 8, 40 for 4 × 10 and 48 for 4 × 12. Windows are usually left in because the cut-outs are rarely reusable. Finishing materials scale with the area: roughly one screw per square foot, 370 ft of tape and 138 lb of premixed compound per 1,000 sq ft.

sheets = (wall length × height − doors + ceiling) × (1 + waste) ÷ sheet area
Waste
10% for cuts and damaged edges, 15% for many corners
Tape
About 0.37 ft per sq ft of board
Compound
About 0.14 lb per sq ft, for three coats

Worked example

A 12 × 14 ft room, 8 ft walls, one door, ceiling included, in 4 × 8 sheets.

  1. 1Walls: 2 × (12 + 14) × 8 = 416 sq ft, less 21 for the door = 395
  2. 2Ceiling: 12 × 14 = 168 sq ft; total 563 sq ft
  3. 3With 10% waste: 619 sq ft ÷ 32 = 19.4, so 20 sheets
  4. 4Tape: 563 × 0.37 = 208 ft; compound: 563 × 0.138 = 78 lb

20 sheets of 4 × 8, about 640 screws, 208 ft of tape and two 4.5 gal pails of compound.

Frequently asked questions

What thickness of drywall should I use?

½ in is standard for walls. Ceilings need ½ in sag-resistant board on joists 16 in apart, or ⅝ in on joists 24 in apart. Walls between a garage and the house usually need ⅝ in Type X fire-rated board; check your local code.

Should I hang drywall horizontally or vertically?

On walls up to 8 ft high, horizontally is usually better: it means fewer seams, and the long factory-tapered edges are easier to hide. For walls taller than 9 ft, vertical sheets can cut the number of butt joints.

How many screws per sheet of drywall?

About 32 for a 4 × 8 sheet on a wall with studs 16 in apart: five or six screws down each stud, 12–16 in apart, and about 8 in apart around the edges. Ceilings need closer spacing. This calculator allows one screw per square foot of board.

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