Drywall Calculator · How it works
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Drywall is hung by the sheet, but the finishing materials — joint compound, tape and screws — are bought by how much board you put up. This calculator does both. It turns your wall and ceiling dimensions into net square footage, converts that to whole sheets with a waste allowance, then scales the finishing materials off the board area you actually install.
Enter the total length of a room's walls (add every wall: 12 + 10 + 12 + 10 = 44 ft), the wall height, and how many doors and windows the room has. The tool multiplies length by height for gross wall area, subtracts the openings, adds the ceiling if you ask for it, divides by the sheet size and rounds up to whole sheets after adding waste.
A 12 × 10 ft bedroom with 8 ft walls, one door, one window, 4 × 8 sheets and a 10% waste factor:
Joint compound — 0.010 gal/SF at Level 4. USG publishes coverage for Sheetrock Brand All Purpose Joint Compound (submittal J1969) as approximately 10 gallons per 1,000 sq ft of gypsum panels, which is 0.010 gallon per square foot. That is the whole three-coat taping operation, not one coat — a 4.5-gallon pail finishes about 450 SF of board, a 5-gallon pail about 500. The calculator targets a Level 4 finish, the smooth result suitable for flat and eggshell paint, as defined in the Gypsum Association's GA-214 Levels of Gypsum Board Finish.
Paper tape — 0.37 LF/SF. USG rates paper joint tape at roughly 370 feet per 1,000 sq ft of panels, or 0.37 linear feet per square foot of board, so a 500-foot roll covers about 1,350 SF. As a check, the seams on a single 4 × 8 sheet work out to about 0.375 LF/SF from the geometry alone, so the manufacturer rate and the arithmetic agree.
Screws — about 1 per SF. One screw per square foot is the standard field-and-edge fastening estimate, roughly 32 screws per 4 × 8 sheet. A pound of 1-1/4" drywall screws holds about 150 of them, though that count is brand- and length-dependent.
How much joint compound do I need per sheet of drywall?
At a Level 4 finish, USG's published rate of about 10 gallons per 1,000 square feet works out to roughly a third of a gallon per 4x8 sheet. A 4.5-gallon pail finishes about 450 square feet of board, or fourteen 4x8 sheets, and that covers the whole three-coat operation rather than a single coat.
How many drywall screws are in a pound?
About 150 for the common 1-1/4 inch screw, though it varies with brand and length. At one screw per square foot you use about 32 on a 4x8 sheet, so a pound fastens roughly four and a half sheets.
Does this calculator include the ceiling?
Only when you tick the ceiling box and enter the room's length and width. The ceiling area is then added to the net wall area before the sheet count is figured, so one estimate covers walls and ceiling together.
What finish level does the compound estimate assume?
Level 4, the standard smooth finish for flat and eggshell paint as defined in the Gypsum Association's GA-214. A heavier skim-coated Level 5 finish uses more compound; a fire-taped Level 1 uses far less.
This is a materials estimate for ordering, not a hanging plan. It assumes rectangular rooms, standard openings and one waste factor across the job; it does not lay out where each sheet goes, account for corner bead, or decide whether a garage or furnace-room wall needs fire-rated Type X board. Check your local code for where 5/8" and Type X drywall are required.
The joint-compound rate on this page is USG's published coverage for Sheetrock Brand All Purpose Joint Compound (submittal J1969), "approximately 10 gal./1,000 sq. ft."; the tape rate is USG's paper-tape coverage of roughly 370 ft per 1,000 sq ft. Finish levels are defined by the Gypsum Association's GA-214, Levels of Gypsum Board Finish. The door (21 SF) and window (15 SF) deductions are standard takeoff allowances. Fuller background on sheet types, three-coat finishing and tools is in our drywall guide.