Drywall Calculator
Sheets, screws, tape and joint compound for a room, plus a comparison of board lengths and the joints each one leaves you.
Sheets, screws, tape and compound for a room — and which sheet length actually leaves you fewer joints, because every joint you avoid is finishing work you never have to do.
Quick answer: drywall sheets by area, 15 % waste
| Net area | 4×8 | 4×10 | 4×12 |
|---|---|---|---|
| 200 ft² | 8 | 6 | 5 |
| 300 ft² | 11 | 9 | 8 |
| 400 ft² | 15 | 12 | 10 |
| 600 ft² | 22 | 18 | 15 |
| 800 ft² | 29 | 23 | 20 |
Net area = walls + ceiling − openings (21 ft² per door, 15 ft² per window in the calculator). Longer sheets leave fewer butt joints, and every joint you avoid is finishing you never do.
| Net area to cover | — |
|---|---|
| With waste | — |
| Sheets | — |
| Screws (approx) | — |
| Joint tape | — |
| Joint compound | — |
| Sheet length comparison | — |
The joint, not the sheet. Screws and compound follow area; joints follow board length. GA‑216‑2010 takes the second coat about 3½ in. past a joint's centre (18.6) and a third, where one is specified, about 6 in. (18.7). Over a tapered edge that 12 in. band sinks into a factory recess and finishes flush. Section 2.1.4 defines an end joint as a cut end where the gypsum core is exposed. There is no recess, so the compound stands proud. That is the Drywall Finishing Council's High Crown, and its only prevention is feathering wide enough to conceal.
The default room, three lengths. Walls alone, hung horizontally, in this page's 12 × 10 room: 108 in. of height takes three 48 in. courses, so two horizontal joints run right round. That is 88 lin ft at any board length. Only the end joints move. A 4×8 leaves 9 ft of end joint on all four walls (staggered between courses per 4.6.5, same total): 36 ft. A 4×10 clears the two 10 ft walls: 18 ft. A 4×12 clears all four: none. So 124, 106 and 88 lin ft of joint, on 544, 560 and 576 ft² of board. The 4×12 buys 32 ft² more board and 36 ft less finishing. The tape row above runs on area and takes in the ceiling and the corners; this is flat wall joint.
Then the width. All three options are 4 ft wide, so all three need three courses on a 9 ft wall and that 88 ft never moves. Two 54 in. courses make 108 in. exactly: one horizontal joint, 44 lin ft, just over a third of the 4×8 figure. CGC, a USG company, sells the width for that reason: no more filler pieces to cut, faster taping and finishing. National Gypsum lists 54 in. only at 12 and 14 ft, so the width brings the length with it, at 70 to 76 lb a board on its published 1.3 to 1.4 lb/ft². Order the width, not just the length.
What I check on a job
Measure the board, not the plan. Before I trust the sheet count I check the perimeter I typed. The perimeter off the plan is not the length of wall that gets board: closet interiors, soffit returns and the jambs around each window all take board, and none of them shows up in a length-times-width loop, so I walk the room and add them in. Then I look at the openings. The page deducts 21 ft² per door and 15 ft² per window, but a 4×12 hung horizontally across a window is still a whole sheet; the opening comes out as offcut, not as a board I didn't have to buy. On a room hung in long sheets I leave the openings in, which on the worked example is 13 sheets instead of 12. Last, the delivery path: before I order 12 ft lengths I measure the stair turn, the hallway corner or the elevator cab they have to get past.
Estimates use ordinary rules of thumb rather than a manufacturer figure, so treat them
as a shopping list, not a specification: about one screw per square foot at 16" o.c. (which is the same 32 on a 4×8 sheet, but stays right on a 4×12), roughly 1 linear foot
of tape per square foot of board, and about 0.05 lb of all-purpose compound per square foot for a
three-coat finish. Deductions are 21 ft² per door and 15 ft² per window.
The sheet-length comparison matters more than the sheet count. Longer boards span further, so a 12 ft
sheet on a 12 ft wall gives you a joint-free run where 8 ft sheets give you a butt joint to tape, float
and sand. That is the slowest, most visible joint there is. Buy the longest sheet you can physically carry
into the room.
Worked example
A room with a 44 ft perimeter, 9 ft walls, a 120 ft² ceiling, one door and two windows: how many sheets?
- Walls = 44 × 9 = 396 ft²; plus the ceiling, 516 ft².
- Deduct a 21 ft² door and two 15 ft² windows: 465 ft².
- 4 × 12 sheets are 48 ft²; with 15% waste, ceil(465 × 1.15 ÷ 48) = 12.
12 sheets of 4 × 12, with screws, tape and compound counted from the same area. Leave the openings in and it is 13.
6 values on this page were driven in a browser and compared with independently derived figures on 2026-10-29 (2808 values across 228 calculators site-wide).
Questions
How many sheets of drywall for a 12 × 12 room?
It depends on wall height and openings. A 44 ft perimeter at 9 ft with one door and two windows is 465 ft² including a 120 ft² ceiling — 12 sheets of 4 × 12 with 15% waste.
Which sheet size leaves fewer joints?
The longest one that fits the wall. 4 × 12 sheets on a 9 ft wall run horizontally with one butt joint fewer than 4 × 8s; the page prints the comparison.
Why are end joints harder to finish than tapered ones?
Because a tapered edge has a factory recess and an end joint does not: GA-216-2010 §2.1.4 defines it as a cut end where the gypsum core is exposed. The compound stands proud of the face, which the Drywall Finishing Council calls High Crown, and the only prevention is feathering wide enough to conceal it.
What is 54-inch drywall for?
Two 54 in. courses make 108 in. exactly, so a 9 ft wall has one horizontal joint instead of two: 44 lin ft in a 12 × 10 room, just over a third of what 4×8 sheets leave. National Gypsum lists the 54 in. width only at 12 and 14 ft, about 70 to 76 lb a sheet.