Free Contractor Tool
Drywall Calculator
Enter your walls and ceilings to get the sheet count for any board size, plus the screws, joint compound, and tape to go with it. Openings and waste are handled for you.
Built by SubcontractorHub — the software contractors use to quote, finance, and run every job.
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Calculate Drywall Sheets and Materials
Add each wall and ceiling, choose your sheet size, and get board count plus fasteners and finishing materials. Results update as you type.
10% is typical
Walls & ceilings to cover
21 sq ft each
15 sq ft each
Materials needed
Sheets to buy
3
Screws
96
Mud (4.5 gal)
1
Board cost
Enter a price above
Net area
60 sq ft
With 10% waste
66 sq ft
Joint tape
24 ft (1 roll)
Mud volume
3.2 gal
Drywall Sheet Sizes
Bigger sheets mean fewer seams to tape and sand — but more weight to lift and more waste when a cut goes wrong.
How many sheets for a 12 × 12 room?
Four 12-foot walls at 8 feet is 384 square feet, and the ceiling adds 144, for 528 total. Take out one door and one window and you are at about 492 square feet.
Divide by 32 square feet per 4 × 8 sheet and you get 15.4 sheets. Add the usual 10 percent for cuts and damaged corners and you should order 17.
Horizontal or vertical?
Hang horizontally on residential walls. It cuts total seam length by up to a quarter, puts butt joints at a comfortable working height instead of running floor to ceiling, and ties more studs together so the wall reads flatter.
Go vertical when a sheet length matches the ceiling height exactly, in fire-rated commercial assemblies, or where a seam has to land on a particular stud.
How Much Joint Compound and Tape?
Budget about 1.7 gallons of ready-mix per 4 × 8 sheet across all three coats — roughly one 4.5-gallon bucket per 85 square feet of board.
Screws and fasteners
At 16-inch stud spacing with screws every 12 inches, a 4 × 8 wall sheet takes about 32 screws. Ceilings need more — 36 to 40 per sheet — because the board is hanging against gravity all day.
Use 1¼-inch screws on ½-inch board over wood framing and 1⅝-inch on ⅝-inch board. Set each head just below the paper without tearing it; a torn face has no holding power and will telegraph through the finish.
Where the waste factor really goes
Ten percent is the standard allowance, and it is rarely generous. Waste comes from cut-offs that are too small to use, corners crushed in transit, sheets damaged during the lift, and the strips left over around windows and doors.
Go to 15 percent on rooms with lots of openings, angled ceilings, or soffits. On a long, simple commercial wall you can safely drop to 5 percent.
From Material Takeoffs to a Signed Proposal
A sheet count is the start of an estimate, not the end of one. SubcontractorHub rolls materials, labor, and markup into a branded proposal your crew can present on a tablet before leaving the site.
Show good-better-best options, offer financing, capture a signature on the spot, and send the signed job straight through to scheduling.
See How It WorksMaterial takeoffs become proposals in minutes
Labor and markup applied automatically
Good-better-best options in one presentation
Financing and monthly payments shown on site
Signed job flows straight to operations
Resources
Related Guides & Tools
Drywall quantities are estimates based on the dimensions, sheet size, and waste factor entered. Fastener, compound, and tape figures use common industry rules of thumb and will vary with framing spacing, finish level, and whether you tape by hand or by machine. Confirm against your own production rates before ordering.
Frequently Asked Questions
- How do I calculate how much drywall I need?
- Add up the total square footage of walls and ceilings you are covering, subtract large openings, then divide by the area of one sheet — 32 square feet for a standard 4 by 8 sheet. Add about 10 percent for waste from cuts and damage. This calculator does all of it and also estimates screws, joint compound, and tape.
- How many sheets of drywall do I need for a 12x12 room?
- A 12 by 12 room with 8-foot ceilings has 384 square feet of wall plus 144 square feet of ceiling, so 528 square feet total. Subtracting a door and a window leaves about 492. Divided by 32 square feet per sheet that is 15.4 sheets — with 10 percent waste, order 17 sheets of 4 by 8.
- How much joint compound do I need per sheet of drywall?
- Plan on roughly 0.053 gallons of ready-mix joint compound per square foot of drywall across all three coats, which works out to about 1.7 gallons per 4 by 8 sheet. A standard 4.5-gallon bucket therefore covers around 85 square feet of board. Machine taping uses less; heavy texture uses considerably more.
- How many drywall screws per sheet?
- About 32 screws per 4 by 8 sheet on walls at 16-inch stud spacing, using 12-inch screw spacing along each stud. Ceilings need more — roughly 36 to 40 per sheet — because the board is fighting gravity. A rule of thumb is one pound of screws per 1,000 square feet is nowhere near enough; budget closer to 5 pounds.
- How much drywall tape do I need?
- Roughly 0.4 linear feet of tape per square foot of drywall, so a 4 by 8 sheet consumes about 13 linear feet. A 500-foot roll of paper tape covers around 1,250 square feet of board. Buy an extra roll — running out mid-seam is worse than having one spare.
- Should drywall be hung horizontally or vertically?
- Hang horizontally in residential work. It puts the butt joints at a comfortable working height, reduces total seam length by up to 25 percent, and ties more studs together for a flatter wall. Hang vertically when the ceiling height matches a sheet length exactly, in commercial fire-rated assemblies, or on walls where a vertical seam must land on a specific stud.