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Drywall Calculator: Sheets, Screws, Tape and Compound

Work out drywall sheets, screws, joint tape and compound for a room, using USG's material table, with the code's fastener spacing and old-home warnings.

Updated
Reading time2 min
Sources verified

Key takeaways

  • Sheets = surface area × (1 + waste) ÷ sheet area, rounded up.
  • Screw and compound amounts come from an older USG table, so treat them as estimates.
  • The IRC limits wall screws to 12 inches where studs are 24 inches apart, which is closer than USG's older figure.

Enter your room's size, measured openings and sheet size. The tool gives sheets to buy, plus fasteners and finishing materials.

  • Sheets to buy18 sheetsFor 507 sq ft, including your waste allowance
  • ScrewsAbout 1.4 lbUSG's rate, at its older spacing assumption
  • Joint tapeAbout 188 ft
  • Joint compoundAbout 70 lbAll-purpose, or about 4.8 gallons of lightweight

Nothing you enter leaves your browser. Fastener and finishing quantities come from an older USG guide, so check your product's data.

Show the math with your numbers
  1. Area: 507 sq ft of walls and ceiling, less openings
  2. Sheets: 507 × 1.1 ÷ 32, rounded up to 18
  3. Screws: 507 × 0.0027 = 1.4 lb
  4. Tape: 507 × 0.37 = 188 ft
What if: waste allowance
Waste allowanceSheets to buy
0%16 sheets
5%17 sheets
10% (yours)18 sheets
15%19 sheets

How the calculator works

  1. Area: 2 × (length + width) × height − openings, plus the ceiling if included
  2. Sheets: area × (1 + waste %) ÷ sheet area, rounded up
  3. Materials: area × USG's rate per square foot
Material Per 1,000 sq ft of panel (USG)
Type W screws 2.7 lb
Joint tape 370 ft
All-purpose ready-mixed compound 138 lb
Lightweight ready-mixed compound 9.4 gal

These come from USG's installation and finishing guide, an older undated copy, so check your product's current data. We default to 10% waste, a rule of thumb from calculator sites rather than a USG figure.

Worked example

A 12 × 12 foot room with 8-foot walls, a 21-square-foot door and the ceiling, using 4 × 8 sheets and 10% waste:

  • Walls: 384 − 21 = 363 square feet
  • With ceiling: 363 + 144 = 507 square feet
  • Sheets: 507 × 1.10 ÷ 32 = 17.4, so 18 sheets
  • Screws: about 1.4 lb. Tape: about 188 feet. Compound: about 70 lb, or 4.8 gallons of lightweight

How sheet size changes your count

For the same 507 square feet with 10% waste:

Sheet Coverage Sheets
4 × 8 ft 32 sq ft 18
4 × 10 ft 40 sq ft 14
4 × 12 ft 48 sq ft 12

Longer sheets can mean fewer joints, but they're heavier and harder to get up stairs and around corners.

Fastener spacing: where sources disagree

USG's older guide lists wall screws at 16 inches. 2021 IRC Table R702.3.5 limits them to 12 inches where wall framing is 24 inches on center. If your studs are 24 inches apart, use the code's figure, as your screw count will be higher. Check the table and your local code for your thickness and framing.

USG also says to keep screws at least 3/8 inch from panel ends and edges.

Older walls and ceilings

Stop before you cut, sand or demolish old surfaces. CPSC says many building products contained asbestos until the 1970s, including textured paint and patching compounds. Old paint can also contain lead. Get advice before you disturb them.

Once your drywall's up, use the paint calculator.

Frequently asked questions

How many sheets of drywall do I need for a 12 × 12 room?

With 8-foot walls, a door and the ceiling, about 18 sheets of 4 × 8 at 10% waste.

How much joint compound do I need?

USG's table gives about 138 lb of all-purpose, or 9.4 gallons of lightweight, per 1,000 square feet.

What thickness should I use?

Requirements depend on framing spacing, location and fire rules. Check your local code and the panel maker.

Sources

We use primary sources where we can: building codes, federal rules and manufacturer documents. Read our editorial standards.