Calculators

Drywall Calculator

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

How it 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.

Related calculators

More in Construction & DIY