Drywall Sheet Count and Waste Calculator

Calculate the number of drywall sheets required for walls and ceilings, accounting for doors, windows, and waste.

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Include Ceiling?

Number of Standard Doors (32" × 80")

Number of Standard Windows (36" × 48")

Sheet Width (ft)

Sheet Length (ft)

Waste Factor (%)

Gross Wall Area = 2 × (Length + Width) × Ceiling Height

Opening Deductions = (Number of Doors × 17.78 ft²) + (Number of Windows × 12 ft²)

Net Wall Area = Gross Wall Area − Opening Deductions

Ceiling Area = Length × Width (if ceiling is included)

Total Net Area = Net Wall Area + Ceiling Area

Sheet Area = Sheet Width × Sheet Length

Sheets (no waste) = ⌈ Total Net Area ÷ Sheet Area ⌉

Sheets Needed = ⌈ (Total Net Area ÷ Sheet Area) × (1 + Waste% ÷ 100) ⌉

Standard door opening assumed to be 32 in × 80 in (≈ 17.78 ft²) per IRC Section R311.
Standard window opening assumed to be 36 in × 48 in (12 ft²); adjust for custom sizes.
Drywall sheets are universally 4 ft wide; lengths of 8, 10, or 12 ft are the most common.
A 10% waste factor is typical for rectangular rooms; increase to 15–20% for rooms with many angles, arches, or complex cuts (NAHB Remodeling Cost Guide).
Ceiling height is assumed uniform throughout the room.
This calculator covers one room. For multi-room projects, run the calculator separately for each room and sum the totals.
Sheet counts are always rounded up to the nearest whole sheet.

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