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Drywall Screw Calculator

Counted off the code table, sheet by sheet.

An estimate of quantity — clause numbers are the IRC's; your local authority decides.

20' · 240 in · 20 ft · 6.096 m

20' · 240 in · 20 ft · 6.096 m

9' · 108 in · 9 ft · 2.7432 m

1,087 ft²

Inch Calculator advises about 10%, which is where this starts. Laid out sheet by sheet, a small room with a ceiling comes nearer 13%; a large room wastes far less. It is added once, to every product on the list.

This page recalculates as you type. There is no Calculate button.

Answer

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Screws

1045 screws

1,087 ft² to board · 31 sheets · 31 × 4 × 10 ft

Buy 31 × 4 × 10 ft sheets
Area to board, net 1,087 ft²
Ticked items cost $693.26
More numbers
With the 10% for cuts 1,195.7 ft²
Joint compound 10.76 gal
Joint tape 442.41 ft
Weight to carry 2,728 lb
DrawingThe project drawn to scale. Garage: 20' × 20'.20'20'Garage

Buying noteGarage is 9 ft tall. Two courses of the 54 in width cover a 9 ft wall exactly, where 4 ft board needs a third course or a ripped strip down the middle. Only USG makes it, and pro yards stock it.
Buying noteScrews are counted sheet by sheet, so a screw on a shared edge is counted twice. The real number is a little lower — the safe side for a shopping list.

Breakdown

Part Measurements Qty Area Share
Garage 20' × 20' × 9', 1 door, 1 window Add ×1 1,087 ft²

What to buy

Buying noteGarage is 9 ft tall. Two courses of the 54 in width cover a 9 ft wall exactly, where 4 ft board needs a third course or a ripped strip down the middle. Only USG makes it, and pro yards stock it.
Buying noteScrews are counted sheet by sheet, so a screw on a shared edge is counted twice. The real number is a little lower — the safe side for a shopping list.

Shopping list

31 31 × 4 × 10 ft (28 to hang + 3 spare) $588.38 Reference price $24.48. Type your store's. Reference price $21.98. Type your store's. Reference price $18.98. Type your store's. Reference price $17.48. Type your store's. Reference price $15.98. Type your store's.
2 1 × 5 lb box + 1 × 1 lb box $35.96 Reference price $26.98. Type your store's. Reference price $8.98. Type your store's.
3 1 × 4.5 gal + 2 × 3.5 gal $55.94 Reference price $19.98. Type your store's. Reference price $17.98. Type your store's. Reference price $14.98. Type your store's.
1 1 × 500 ft roll $12.98 Reference price $12.98. Type your store's. Reference price $7.98. Type your store's.
Ticked items $693.26

Untick what you already have. Each row has its price beside it — type what your store charges.

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Cutting list

Every sheet size, hung on your walls and ceiling the way the form asks - in rows across the studs, or upright along them - with the offcut of one row starting the next; each size's cost is the sheets it hangs, before the spares the waste adds in the list above. Doors and windows are hung over and cut out after, so they save no sheet. The 54 in width is offered and never picked for you: it is a pro-yard item, and two rows of it cover a 9 ft wall.

26 × 4 × 10 ft 0" thrown away
13 × 10'
13 × 10'
Sheet layoutEach bar is one sheet, drawn to scale along its length, with the rows cut from it and the end left over.x1310'x1310'

Standards

We hold the criteria and the clause, not the wording of the standard.

Meets IRC 2021 · R702.3.5

Screws at 16 in on walls framed 16 in, which is what the table allows.

Meets IRC 2021 · R702.3.5

At 16 in framing the table lists ceiling board either way, along the joists or across them.

Not checked IRC 2021 · R702.3.5

If this is a garage ceiling with a habitable room over it, the table asks for 5/8 in Type X run across the framing with fasteners at 6 in — half the usual spacing. Whether the room above is a habitable one is not something a measurement can tell us.

How this was worked out

Every number below is yours. Each constant links to the row where you can change it.

Garage 2 × (20' + 20') × 9' − 21 ft² − 12 ft² + 20' × 20' 1,087 ft²

Change:One door openingOne window opening

With the waste for cuts 1,087 ft² × (1 + 10%) 1,195.7 ft²
Sheets to buy 26 × 4 × 10 ft hung in rows with nothing left over, 28 sheets with the strip rows ripped from whole ones × (1 + 10%) 31 × 4 × 10 ft
Screws (walls 687 ft² × 32 a sheet ÷ 40 ft² + ceiling 400 ft² × 40 a sheet ÷ 40 ft²) × (1 + 10%) 1045 screws → 1 × 5 lb box + 1 × 1 lb box

Change:Screw spacing, wall at 16 in o.c.Screw spacing, ceiling

Joint compound 1,087 ft² × 0.009 gal/ft² × (1 + 10%) 10.76 gal → 1 × 4.5 gal + 2 × 3.5 gal

Change:Compound per unit area

Joint tape 1,087 ft² × 0.37 ft/ft² × (1 + 10%) 442.41 ft → 1 × 500 ft roll

Change:Tape per unit area

Weight of the sheets 31 × 40 ft² × 2.2 lb/ft² 2,728 lb

Change:Board weight, 5/8 in Type X

What it comes to 31 × $18.98 + 1 × $26.98 + 1 × $8.98 + 1 × $19.98 + 2 × $17.98 + 1 × $12.98 $693.26

Assumptions

Every one of these is editable. Change one and the answer changes with it.

Assumption Value Confidence
Board weight, 5/8 in Type XNominal weight of 5/8 in Type X board. USG Sheetrock Firecode X product page; Gold Bond Fire-Shield submittal 111098 (05/23). lb/ft² From a data sheet or an agency document
One door openingA 3 x 7 ft opening; Benjamin Moore takes 21 ft² for a door too. The paint cluster takes 20 ft², the finished leaf, because paint stops at the casing and board is cut to the opening. Neither 20 nor 21 is a measured rough opening: both are conventions, and the box is there for anyone who has measured theirs. ≈ ft² Trade convention
One window openingA 3 x 4 ft window. Benjamin Moore takes 12 ft² as well, Sherwin-Williams 15. Inch Calculator's drywall page has no opening box at all. ≈ ft² Trade convention
Screw spacing, wall at 16 in o.c.IRC Table R702.3.5, wall, framing 16 in o.c., application without adhesive: screws not more than 16 in apart. Same figure in the IRC 2021 and IRC 2024 text. in From a data sheet or an agency document
Screw spacing, ceilingIRC Table R702.3.5, ceiling, without adhesive: screws not more than 12 in apart, at 16 and at 24 in framing alike. Same figure in the IRC 2021 and IRC 2024 text. in From a data sheet or an agency document
Screws in a pound, 1-5/8 inGrip-Rite coarse thread drywall screw table, #6 x 1-5/8 in, the length for 5/8 in board: 200 per pound. Retail listings print lower counts (189 per pound in a 5 lb box of 945). screws/lb From a data sheet or an agency document
Compound per unit areaUSG's FAQ gives two 4.5 gal pails of UltraLightweight All Purpose compound per 1,000 ft² of board, which is 9 gal per 1,000 ft². It is one maker's rule of thumb for one product in a FAQ rather than a coverage off a data sheet, and a setting-type compound mixed from powder will differ. Inch Calculator works in lb/ft² and publishes no figure, so there is nothing of theirs to compare. ~ gal/ft² Derived or single-supplier
Tape per unit areaUSG Sheetrock Heavy joint tape data sheet: 370 ft per 1,000 ft² of board, which is 0.37 ft of tape per square foot. ft/ft² From a data sheet or an agency document

How many drywall screws a room takes

The spacing is not one number. IRC Table R702.3.5 gives it by plane and by framing: half-inch board on a wall framed 16 inches on center takes screws every 16 inches, and the same board on a ceiling takes them every 12. On framing at 24 inches on center the wall figure tightens to 12 as well.

So the count is worked out sheet by sheet, and the two numbers come out different:

  • A 4 by 8 sheet standing upright on a wall framed 16 in o.c. has four stud lines across its width, with seven screws down each — 28 screws.
  • The same sheet on a ceiling runs across the joists: seven joists cross its length, with five screws down its width — 35 screws.

A bigger sheet has fewer edges for its area, so it takes fewer screws a square foot: a 4 by 12 takes 40 on a wall and 50 on a ceiling for 48 square feet. The page counts on the sheet it hangs. For the 12 by 10 foot room this page opens with — 319 square feet of wall and 120 of ceiling, hung in 4 by 12s — that is 430 screws with the waste, which buys as two 1 pound boxes; in 4 by 8s it is 452.

What the table says

Board Plane Framing Screws apart
½ inWall16 in o.c.16 in
½ inWall24 in o.c.12 in
½ inCeiling16 or 24 in o.c.12 in
⅝ inWall16 in o.c.16 in
⅝ inCeiling16 or 24 in o.c.12 in

Those are the figures for board fastened without adhesive, read in the IRC 2021 and IRC 2024 text, which give the same numbers under the same clause. Screws must be Type W or Type S under ASTM C1002; the clause numbers and the limits are repeated here, the wording is the ICC's. With adhesive the table allows wider spacing, which this page does not offer: it is easy to switch on and hard to be sure of, and a ceiling fastened for adhesive that was not applied is a ceiling on the floor.

Counting on the safe side

Counting sheet by sheet counts a screw on a shared edge twice, because the sheet on each side of the joint claims it. The real number is a little lower than the one printed. That is the right side to be wrong on for a shopping list, and the page says so under the answer rather than leaving you to work it out at the counter.

Which screw, and how many to a box

Half-inch board takes a #6 by 1¼ inch coarse-thread screw; ⅝ inch board takes 1⅝ inch. Grip-Rite's product table gives 258 to the pound for the shorter and 200 for the longer, which is how the boxes here are counted — so switching the board switches both the screw and the count. Retail boxes print lower numbers on the label (238 in a 1 pound box, 945 in a 5 pound), and the count printed on the box is the one that governs at the till.

Prices are our own estimates, not a store's. We are not connected with any brand or store named here.