EstimatorKitFree drywall calculator
Board a room, and count the joints first
Give a room its length, width and ceiling height and this hangs it: sheets for four walls and the ceiling, minus the openings, plus the screws, joint compound, tape and corner bead that go with them. Before it commits to a size it hangs the same room three times, in 8, 10 and 12 ft board, and shows what each length costs in butt joints — the square-end joints that have to be floated 24 in wide because there is no taper to hide them. A room whose walls are shorter than the board can have none at all.
- 100% free
- No signup
- Walls and ceiling
- 3 board lengths compared
- Screws, mud, tape, bead
Wall to wall, floor to ceiling. An odd-shaped room is easier to add up in the square footage calculator first and enter as an equivalent rectangle.
1.6 lb a square foot — 1/2 in regular gypsum board.
Longer board means fewer joints and heavier lifts. Both are shown below before you pick.
Half is the takeoff compromise: the strip above a door usually goes back above that door, the piece cut out of a window rarely goes anywhere.
Adjust the fastening and finishing rates
Board for 559 sq ft of wall and ceiling
18 × 48 in × 12 ft
- Hung, before the allowance
- 16
- Allowance
- +10%
- Screws
- 1 × 5 lb (1.8 lb)
- Joint compound
- 2 × 4.5 gal (63 lb)
- Joint tape
- 1 × 250 ft
- One sheet weighs
- 77 lb
| Length | Sheets | Butt joints | Lift |
|---|---|---|---|
| 8 ft | 22 | 11 (44 lf) | 51 lb |
| 10 ft | 22 | 11 (44 lf) | 64 lb |
| 12 ft | 16 | 4 (16 lf) | 77 lb |
Why that length
12 ft board leaves 4 butt joints, the fewest any stocked length manages on this room. At 12 ft you are hanging 4 butt joints over 16 linear feet, against 88 feet of tapered joint. Each butt foot is floated about 24 in wide to hide the bump; each tapered foot is filled in a 10 in band and forgets about it.
A 48 in × 12 ft sheet of 1/2 in regular is 77 lb. That is the trade-off nobody writes down: the length that finishes fastest is the one two people have to get round a stairwell.
Tape is counted off the joints rather than off the sheets: 88 lf of tapered joint, 16 lf of butt, 52 lf of wall-to-ceiling angle and 32 lf of vertical corner — 188 lf in all, which works out at 10.4 ft a sheet on this room. Outside corners are not in that figure; they take bead.
Screw count uses 320 to the pound — the count on a 1 lb box of #6 × 1 1/4 in coarse-thread bugle-head drywall screws, and it varies with length and thread — 1 5/8 in screws for 5/8 in board run nearer 230 to the pound. Compound boxes use 61.7 lb — the net weight printed on a 4.5 gallon box of ready-mixed all-purpose joint compound. Tape rolls use 250 ft — a standard roll of paper joint tape.
Net board area divided by one sheet gives 12, which is the floor rather than the order — it assumes every offcut lands on another wall at the same height.
Sheet coverage, for checking against a quote: 4 × 8 is 32 sq ft, 4 × 10 is 40, 4 × 12 is 48. At 54 in wide each of those goes up by an eighth.
How to work out how much drywall a room needs
Measure the room, pick the length by its joints, then let the joints price the finishing.
Take the room off: four walls, the ceiling, and what comes out of them
Length, width and floor-to-ceiling height give the gross surface, and the ceiling can be switched out for a basement getting a suspended grid instead. Doors and windows come off at a standard 21 and 15 sq ft, and the three deduction settings exist because none of them is right for every job: taking the full area off assumes the cut-out gets reused, taking nothing off assumes it never does, and half sits where most takeoffs land.
Let the length be chosen by the joints, not by the aisle
The table under the result hangs the same room in 8, 10 and 12 ft board and reports three things for each: sheets, butt joints, and what one sheet weighs. Pick the length yourself or leave it on the joint-count setting. A room whose walls are shorter than the board has no butt joints on those walls at all, and that is a different job to finish from one with eleven of them.
Read the finishing off the joints it actually found
Screws come from the sheet count, compound from the sheet count, and tape from the joint schedule — tapered feet, butt feet, the wall-to-ceiling angle and the four vertical corners added up separately, because a per-sheet tape rate has no way of knowing that a room with one long wall has half the corners of a room with four short ones. Everything is then converted into what a counter sells: pound boxes, 4.5 gallon boxes, 250 ft rolls and uncut bead sticks.
Technical specifications
| Board sizes | 4 × 8, 4 × 10 and 4 × 12 ft, plus a 54 in width that closes a 9 ft wall in two courses |
|---|---|
| Sheet coverage | 32, 40 and 48 sq ft at 48 in wide; an eighth more at each length in 54 in |
| Board weight | 1.6 lb/sq ft for 1/2 in regular, 1.2 lightweight, 2.2 for 5/8 in Type X — so a 4 × 12 of 5/8 in is 106 lb |
| Joint schedule | Butt joints, tapered joints, the wall-to-ceiling angle and four vertical corners counted separately, in linear feet |
| Length comparison | Sheets, butt joints and lift weight for 8, 10 and 12 ft side by side before you choose |
| Fastening | 32 screws a sheet at 12 in spacing, converted at 320 to a 1 lb box of #6 × 1 1/4 in coarse |
| Finishing | 3.5 lb of all-purpose compound a sheet for a level 4, into 61.7 lb boxes; tape into 250 ft rolls |
| Openings | Doors at 21 sq ft and windows at 15, deducted in full, at half, or not at all |
Frequently asked questions
How many sheets of drywall do I need for a 12 by 14 ft room?
Sixteen sheets of 4 × 12 with the ceiling boarded, against twenty-two of 4 × 8 — and the reason to care is that the 12 ft board leaves four butt joints where the 8 ft board leaves eleven. The room is 584 sq ft gross across walls and ceiling, so a plain division asks for thirteen 4 × 12 sheets or nineteen 4 × 8 — under the laid-out count both times, because a wall 2 ft longer than the board still needs a second sheet in every course of it. A door and two windows take about 25 sq ft off at the half setting, which is not a whole sheet in either size and so changes nothing.
Should drywall be hung horizontally or vertically?
Horizontally in a house, vertically in most commercial work, and the reason is the tapered edge. Laid flat, the long tapered edges of two sheets meet in one continuous horizontal line at about 4 ft, which is a comfortable working height, and there is roughly a quarter less joint to finish than standing the same sheets up. Vertical hanging exists because metal-stud partitions with fire ratings are tested that way and because a wall taller than the board is going to have a horizontal joint regardless. On a 9 ft wall, three courses of 48 in board means two horizontal joints and a 1 ft rip along the top, where two courses of 54 in board means one joint and no rip — which is the argument the width setting on this page exists to make.
What is a butt joint and why does it matter so much?
It is the joint where two cut ends meet, and it matters because there is no taper there to hide the tape. The long edges of a sheet arrive from the factory recessed, so a tapered joint is a shallow trough that filling brings back flush in a band about 10 in wide. Two square ends meeting leave the tape and three coats standing proud of the wall instead, and the only way to make that invisible is to crown it — feather the compound out roughly 24 in either side so the eye reads a very slight hill rather than a ridge. That is more mud, much more sanding, and it is what people mean when they say a room finished badly.
Do you subtract doors and windows from a drywall estimate?
Only when they add up to a whole sheet, because the board around an opening comes out of sheets you have already bought. A 3 by 7 door is 21 sq ft, two thirds of a 4 × 8 sheet, and the strip cut out above it is exactly the piece that goes back above that same door — so nothing is saved and nothing is wasted. Deduct it in full and the order comes up a sheet short on a room with several openings; deduct nothing and a wall of glass is paid for twice. The half setting is the working compromise, and the sheet count only moves once the deduction crosses the coverage of one board.
Is 1/2 in or 5/8 in board right for this room?
Half inch on the walls and five eighths on the ceiling is the usual split, and the ceiling half of it is not a preference. Half-inch board on framing at 24 in on center sags between the joists, and GA-216 does not permit it there under a water-based texture — the fixes are 5/8 in, board sold specifically as sag-resistant ceiling board, or strapping the ceiling down to 16 in first. Five eighths Type X is also what the IRC asks for on a garage ceiling with living space above it. The cost is weight: a 4 × 12 sheet of 5/8 in is 106 lb against 77 lb in half inch, which is the difference between two people and three.
How much compound, tape and screw does a room take?
About 3.5 lb of all-purpose compound and 32 screws per sheet, and tape by measuring the joints rather than by multiplying anything. The compound figure covers tape plus three coats at a level 4 finish, which is what flat and eggshell paint want; a level 5 adds a skim over the whole surface — a fourth coat by area rather than by joint — and puts the compound up by roughly a third. Screws convert at about 320 to a 1 lb box of #6 × 1 1/4 in coarse thread, so a room takes pounds rather than boxes of a few. Tape is the one nobody should take off a per-sheet rate, because it is set by the shape of the room: the angle where the walls meet the ceiling and the four vertical corners can be more tape than the field joints are.
Why does 54 in wide drywall exist?
For 9 ft walls, which two courses of standard 48 in board cannot cover without a third strip. A 9 ft wall hung in 4 ft board is two full courses and a 1 ft rip along the top — an extra horizontal joint, an extra run of tape, and a course of narrow offcuts that mostly go in the skip. Two courses of 54 in board make 108 in exactly, so the wall closes with one horizontal joint and no filler. The catch is availability and weight: 54 in stock is a special order in a lot of places, and every sheet is an eighth heavier than the 48 in equivalent of the same length.
About taking a room off, and the joint that decides how long it takes
A drywall takeoff is two surfaces and a subtraction. Walls are the perimeter times the ceiling height, the ceiling is the footprint, and the openings come off — except that the subtraction is the part estimators argue about, because board removed from a wall is not board saved. The piece cut out above a door is the piece that goes back above that door; the piece cut out of a window opening usually is not, because it comes out of the middle of a sheet in two directions. So an opening only changes the order once the deduction reaches the coverage of one whole board, which for a 4 × 12 is 48 sq ft — more than two doors’ worth. That is why this page takes half by default and shows the sheet count without moving until the deduction earns it. Rooms that are not rectangles are easier added up as pieces first in the square footage calculator and entered here as the equivalent box.
The decision that actually costs money is made at the rack, and almost nobody makes it deliberately. Sheets arrive with their long edges recessed at the factory, so where two long edges meet the tape sits in a shallow trough and three coats bring it back flush in a 10 in band. Where two square-cut ends meet there is no trough, the tape stands proud, and the only way to hide it is to crown the joint — feather compound out about two feet each side so the wall reads as a very slight rise instead of a ridge. Buy board that spans the wall and those joints do not exist: a 12 ft room hung in 12 ft sheets has none, while the same room in 8 ft board picks up one in every course of every wall. Hanging the sheets flat rather than upright is the same argument in the other direction, since laid horizontally the long tapered edges do the work and there is around a quarter less joint in the room. The counterweight is what a long sheet weighs: 48 sq ft of 5/8 in Type X is 106 lb, and no joint schedule is worth dropping a board down a stairwell for.
Finishing quantities follow from that schedule rather than from the area. Screws and compound scale with sheets — about 32 and 3.5 lb each — and both are worth adjusting, because a ceiling screwed tighter at the edges runs above the first figure and a level 5 skim coat, which is a fourth coat applied to the whole surface rather than to the joints, runs about a third above the second. Tape does not scale with sheets at all: it is the tapered feet plus the butt feet plus the perimeter where walls meet ceiling plus the four vertical corners, and in a small room those last two are most of it. Corner bead is counted differently again, one uncut stick per outside corner, because a bead spliced part way up a chase cracks along the splice within a year. Once the walls are closed, what happens to them is somebody else’s arithmetic — the paint calculator for coverage, tile for a bathroom wall and flooring for what goes down afterwards — and what is behind them, the structural panel on the other face of the same studs, is counted in courses on the plywood calculator.
What happens to the room you measured
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type — measurements, quantities, the prices your supplier quoted you — is uploaded, logged or kept, which is also why the calculators carry on working on a site with no signal.
The board weights, the coverage figures and the GA-216 ceiling restriction are all compiled into this page, so the takeoff still runs on a gutted house with no power and a phone on one bar.