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Drywall calculator

Drywall sheet calculator

Wall and ceiling dimensions in, sheet and waste assumptions applied, board count out. Updates as you type.

Walls & ceiling inputs

Enter up to 4 wall lengths. Leave a wall at 0 if unused.

Sheet & waste settings

4×8 = 32 sf, 4×10 = 40 sf, 4×12 = 48 sf per sheet.
Typical range 8–15%. Add more for cut-heavy rooms.
Leave at 0 to auto-estimate 8 outside corners × wall height. Enter an actual LF total to override.
Download CSV
Gross wall area
720
Sq ft
Ceiling area
0
Sq ft
Openings deduct
102
Sq ft
Net area
618
Sq ft
Sheets needed
22
Sheets (w/ waste)
Screws
704
Qty @ 16" OC
Drywall tape
229
Linear ft
Joint compound
33
Gallons (L3)
Corner bead
72
Linear ft
Show methodology & assumptions

Formulas

  • Gross wall area = (W1+W2+W3+W4) × wall_height
  • Ceiling area = ceiling_length × ceiling_width (only when Include ceiling is checked)
  • Openings deduction = doors × 21 sf + windows × 15 sf (standard 3×7 door, typical residential window)
  • Net area = max(wall + ceiling − deductions, 0)
  • Sheets = ceil(net_area × (1 + waste) / sheet_sf)
  • Screws = sheets × (32 for 4×8, 40 for 4×10, 48 for 4×12) (16" OC framing: 8 perimeter + 24 field on a 4×8)
  • Tape = 370 LF per 1,000 sf of net area × (1000 sf) (USG/NGC typical for Level 3)
  • Joint compound = 0.053 gal/sf × net_area (USG readymix Level 3 baseline, ~3 coats)
  • Corner bead = override if > 0, else 8 × wall_height (8 outside corners assumed)

Sources & references

  • USG Sheetrock Brand joint compound coverage tables (0.05–0.06 gal/sf for Level 3).
  • Gypsum Association GA-216 fastener spacing for 16" OC framing.
  • Standard 21 sf deduction for a 3×7 interior door; 15 sf for a mid-size window is a conservative average.

What this does NOT account for

  • Gable ends, soffits, bulkheads, furred walls, or shaft wall assemblies.
  • Fire-rated or moisture-resistant board upgrades (multiply compound & labor accordingly).
  • Control joints, L-bead, J-bead, or tear-away bead.
  • Access panel framing and patch material.

Drywall quantity FAQs

How many sheets of drywall do I need for a 12x12 room?
A 12x12 room with 8-ft ceilings has 384 sf of wall. After one door (−21 sf) and one window (−15 sf), net is ~348 sf. With 10% waste that is 12 sheets of 4×8 for the walls, plus 5 more if you board the 144 sf ceiling. Enter your own dimensions above for the exact count.
How do you calculate how much drywall you need?
Sum wall length × height for every wall, add ceiling area if boarded, subtract 21 sf per door and ~15 sf per window, divide by sheet area (32/40/48 sf), round up, and add 8–15% waste. That is exactly what this calculator does — with screws, tape, and mud thrown in.
What waste factor should I use for drywall?
8–15% for typical rooms. Long simple walls run near 8%; corner-heavy rooms, soffits, and stairwells run 15%+. Commercial estimators commonly carry 10–12% on standard partition work — see the waste factor cheat sheet.
How many screws per sheet of drywall?
About 32 screws per 4×8 sheet on 16" OC framing (8 perimeter + 24 field, per GA-216 spacing). A 4×10 takes ~40, a 4×12 ~48.
What will the drywall cost once I know the sheet count?
Take the net area from this tool into the drywall cost calculator — it applies 2026 sheet pricing, hang and finish labor by level, and regional factors to give total installed cost and $/sf.

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