Free estimate — verify against local code before building
Drywall Calculator
Sheet count with waste, plus screws, mud, tape, and corner bead.
What this calculator includes
Enter room dimensions, surfaces, representative openings, panel size, and outside corners. The calculator separates gross area, opening deductions, waste-adjusted board area, exact sheets, whole-sheet rounding, and editable fastener, joint-compound, and tape coverage. Starting values are planning assumptions; the selected rated or nonrated assembly, manufacturer instructions, finish level, and job conditions govern.
How to use this drywall calculator
- 01
Measure the room
Measure length, width, and ceiling height in feet. Include the ceiling unless it's staying or getting a different finish.
- 02
Count the openings
The starting allowances represent a 3 by 7 ft door and 3 by 5 ft window. Edit them for the project, and consider whether small cutouts actually reduce purchased sheets.
- 03
Pick a sheet size
4×12 sheets mean fewer joints to tape on long walls; 4×8 sheets are easier to carry solo and fit through stairwells. Match sheet length to wall length where you can.
- 04
Keep the waste factor
Use 10% only as an editable starting point. Room geometry, sheet orientation, openings, handling damage, repairs, and stocking constraints determine the allowance.
Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- USG Sheetrock Gypsum Panels Installation and Finishing Guide (opens in a new tab)
Manufacturer installation guidance and estimating tables for screws, joint tape, compound, and gypsum-panel area.
- USG Sheetrock Wallboard Estimator (opens in a new tab)
Manufacturer estimator noting that waste and installation practices must be evaluated separately.
- NIOSH Drywall Sanding Dust Controls (opens in a new tab)
Drywall sanding exposure hazards and engineering-control information.
Frequently asked questions
How many sheets of drywall do I need for a 12×12 room?
About 17 sheets of 4×8 drywall for walls and ceiling with 8 ft ceilings. That's 348 sq ft of net wall (after one door and one window) plus a 144 sq ft ceiling — 492 sq ft, times 10% waste is 541 sq ft, divided by 32 sq ft per sheet.
How many screws per sheet of drywall?
The calculator starts at 32 screws per sheet and 200 screws per pound to preserve a familiar planning estimate, but panel size, walls versus ceilings, framing spacing and material, layers, adhesive, rated assemblies, fastener type, and the approved schedule can change both values.
How much joint compound do I need?
The starting value is 500 sq ft of installed board per selected bucket, consistent with USG guidance of about two 4.5-gallon pails per 1,000 sq ft for one lightweight product. Product, finish level, bead, tools, skill, and job conditions change yield, so coverage and bucket weight are editable.
What size drywall sheet should I use?
Panel length affects handling and joint count, but thickness, type, layers, orientation, support spacing, moisture exposure, sag resistance, and fire/sound performance must come from the approved assembly and manufacturer instructions.
Should I hang drywall vertically or horizontally?
Orientation is assembly- and application-specific. Follow the panel manufacturer's instructions and the tested or approved assembly, especially for rated, multilayer, shaft, ceiling, and non-wood-framing work.