Drywall Calculator

How many 4×8, 4×10 or 4×12 drywall sheets you need for a room’s walls and ceiling, minus doors and windows, with waste and cost.

e.g. one 3×7 ft door (21 ft²) + one 3×5 ft window (15 ft²).
%
$per sheet
Your rate is remembered on this device.
Sheets needed (incl. waste)
15 sheets
Sheets before waste
13.6 sheets
Area to cover
436
Estimated board cost
$225.00
Excludes screws, tape, joint compound and labor.

Estimate generated with SortedSums: https://sortedsums.com/drywall-calculator/. For informational purposes only; verify before relying on it.

Estimate only. This tool is for informational and educational purposes. Results depend on your inputs and simplifying assumptions, and are not a substitute for professional engineering, design or financial advice. Always verify with a qualified professional and applicable codes before purchasing, building or making decisions.

How it’s calculated

Wall area = 2 × (length + width) × height − openings Total = walls + ceiling (length × width) Sheets = ⌈ total ÷ sheet area × (1 + waste%) ⌉

Example: a 12 × 10 ft room with 8 ft walls: 2 × 22 × 8 = 352 ft² − 36 ft² of openings = 316 ft², plus a 120 ft² ceiling = 436 ft². With 4 × 8 sheets (32 ft²): 13.6 sheets; with 10% waste 15 sheets.

Gypsum board is made 4 ft wide in lengths from 8 to 16 ft. Longer sheets mean fewer butt joints to finish but are heavier to hang.

Frequently asked questions

How many sheets of drywall do I need for a 12x12 room?

With 8 ft walls: 2 × 24 × 8 = 384 ft² of wall plus 144 ft² of ceiling = 528 ft². That is 16.5 sheets of 4 × 8 before openings and waste, so about 17–19 sheets.

Should I use 4x8 or 4x12 drywall?

4×12 sheets cover a 12 ft wall or ceiling in one piece, reducing joints, but they weigh roughly 50% more. 4×8 sheets are easier for one person to handle.

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Sources

Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.

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