Drywall Sheet Calculator

Estimate 4×8 drywall sheets for room walls and ceiling, deduct fixed door and window areas, and include waste, tape and compound estimates. Calculate it clearly with Figur.

Estimate drywall for walls plus the ceiling

For a rectangular room in feet, wall area is 2 × (length + width) × height and ceiling area is length × width. Both are always included. Subtract 21 sq ft per door and 15 sq ft per window, then multiply the remaining area by (1 + waste ÷ 100). Divide by 32 and round up for 4×8 sheets. Tape and ready-mix compound are rough allowances: round up order area × 0.37 feet of tape and × 0.053 pounds of compound.

Method and assumptions

Net area = 2 × (length + width) × height + length × width − 21 × doors − 15 × windows. Order area = net area × (1 + waste ÷ 100); sheets = round up(order area ÷ 32).

  • The room is rectangular; all four walls and one ceiling are included. There is no walls-only switch.
  • Doors deduct 21 sq ft each and windows 15 sq ft each, regardless of their actual dimensions. Opening counts are whole numbers.
  • Sheets cover 32 sq ft each. Layout, sheet orientation, seams and offcut reuse are not optimized.
  • Tape and compound rates use waste-adjusted area, not an actual joint layout. Verify finishing needs and fire or moisture ratings separately.

Planning takeoff, not a binding bid, structural design or engineering advice. Confirm field measurements, product coverage, installation requirements and supplier quantities before buying.

Sources and references

The result uses your inputs and the tool's documented assumptions; it does not fetch current prices, rates or products.

Worked example

A 12 × 10 ft room is 8 ft tall, with 1 door, 2 windows and 10% waste.

Walls: 352 sq ft; ceiling: 120; openings: 51. Net 421 × 1.10 = 463.10 sq ft. Round up 463.10 ÷ 32 to 15 sheets, 171.347 to 172 ft of tape and 24.5443 to 25 lb of compound.

Frequently asked questions

Can I exclude the ceiling or choose 4×12 sheets?

Not in this tool. Its takeoff always includes the ceiling and assumes 4×8 sheets. Use a separate measured takeoff when those assumptions do not fit.

Does it use my opening dimensions?

No. It deducts 21 sq ft per door and 15 sq ft per window. Oversized or unusual openings need a manual adjustment outside this calculator.

Are tape and compound exact?

No. They are rounded-up rules of thumb based on order area, not seam lengths, finish level or product specifications.

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