Carpentry Calculators

Drywall calculator

Enter the room, its doors and windows, and the sheet size you are buying. This counts the sheets for the walls and the ceiling, and the compound, tape and screws to finish them.

ft
ft
ft
Hanging
in
in
in
in
Sheet size
%

Offcuts and breakage, 10–15% is usual

sq ft/pail

Per 4.5 gal pail of all-purpose — a rule of thumb, edit to suit

About 32 on walls at 16" o.c.; ceilings take more

4×8 sheets, 10% waste included

19sheets

Walls

13 sheets

Ceiling

6 sheets

Board area

540 sq ft

Name this job

Saved jobs stay in this browser. Nothing is sent anywhere, and a save is not a backup — a link is how you move one to another device.

Where the number comes from

Walls, grossPerimeter times ceiling height
416 sq ft
Doors and windows1 at 36" x 80", 2 at 36" x 48"
44 sq ft
Walls, net
372 sq ft
Ceiling
168 sq ft

Walls and ceiling are each rounded up to whole sheets on their own, because an offcut from one rarely finishes the other.

To finish it

Joint compound4.5 gal all-purpose, at 447 sq ft a pail
2 pails
Paper tape1 roll of 500 ft, at about 370 ft per 1,000 sq ft
200 ft
Drywall screws32 per 4×8 sheet, charged by area
540

These are rules of thumb from the gypsum makers' own estimating tables, not measurements of your job. Lightweight compound, a skim coat or a heavy hand all move the mud figure; the fields above are there to be changed.

Where to buy this

This searches the material, not a thickness we worked out for you — 1/2" is the usual wall board, and ceilings often want 5/8" or a sag-resistant 1/2".

Plain search links, nothing sponsored. Prices and stock are the shop's, and a local lumberyard will usually beat both on solid stock.

About drywall quantities

How many sheets of drywall do I need for a 12x14 room?
With an 8 ft ceiling, one 36" x 80" door and two 36" x 48" windows, 19 sheets of 4x8 with 10% waste: 13 for the 372 sq ft of wall and 6 for the 168 sq ft ceiling. In 4x12 sheets the same room is 13. Walls and ceiling are rounded up separately, because an offcut from one rarely finishes the other.
Should I subtract doors and windows from a drywall estimate?
This calculator does, because a door you have counted is a door you expect to be counted. Plenty of drywallers do not bother, and let the cut-outs be the waste — a window's offcut is rarely a piece you can use anywhere else. If you would rather estimate that way, set the door and window counts to zero and keep the waste figure where it is.
4x8 or 4x12 drywall?
Longer sheets mean fewer butt joints, and butt joints — where two factory ends meet without the tapered edge — are the hardest seams to finish flat. That is why 4x12 is the usual choice for walls and ceilings where it can be carried in and lifted. 4x8 is the one a single person can handle, and the one that fits in a car and up a narrow stair. Try both sizes in the calculator: the area is the same either way, and every sheet you do not hang is a seam you do not tape.
How much joint compound and tape does drywall take?
As a rule of thumb from the gypsum makers' estimating tables, about 370 ft of tape per 1,000 sq ft of board, and a 4.5 gal pail of ready-mixed all-purpose compound for roughly every 447 sq ft. For the 540 sq ft room above that is 200 ft of tape — 1 roll — and 2 pails. Lightweight compound, a skim coat or a heavy hand all change the mud figure, which is why it is a field you can edit.
How many screws per sheet of drywall?
About 32 per 4x8 sheet — roughly one per square foot — on walls framed 16" on centre with screws every 16" along each stud. The 2021 IRC (Table R702.3.5) allows 16" spacing on walls but asks for 12" on ceilings, so a ceiling takes more. The calculator charges screws by the square foot, so a 4x12 sheet gets half as many again as a 4x8.

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