Drywall Calculator
Wall area is length times height times the number of walls. Divide by sheet length times sheet width, then apply waste and round up. Openings are omitted. Estimate only, not a hanging plan or code approval.
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How to estimate drywall sheets
- Enter one wall's length and height in the same unit as the sheet. The default room is 12 by 8.
- Enter how many such walls. Four walls of 12 by 8 is a simple box, including no ceiling.
- Enter sheet length and width. A common sheet is 8 by 4. Waste is 0 to 40 percent.
- Read wall area, sheets before waste, and sheets to buy. Paint gallons are a different page. Estimate only.
Drywall sheet count
Rectangle walls, no openings, waste rounded up
| Wall area | length × height × walls |
|---|---|
| Sheet area | sheet length × sheet width |
| Raw sheets | wall area / sheet area |
| Buy | ceil(raw × (1 + waste/100)) |
| Default sketch | Four 12 by 8 walls, 8 by 4 sheets, 10% waste |
| Omitted | Doors, windows, ceiling, and orientation waste |
What this drywall count covers
Each wall is a rectangle. Multiplying by wall count treats every wall as the same size. A ceiling is another rectangle you would add as extra walls or a second pass. Doors and windows stay in the area unless you reduce length or height yourself. Finish coats are the paint calculator. Floor area is square footage.
How sheets to buy are computed
area = length × height × walls. sheet = sheetLength × sheetWidth. raw = area / sheet. buy = ceil(raw × (1 + waste/100)). Waste stays from 0 to 40. Wall count must be greater than 0. Units must match. A 4 by 8 sheet typed as 4 and 8 in feet with walls in inches will not count.
Sheets, waste, and hanging
Horizontal versus vertical hanging changes offcuts. 54-inch boards and 12-ft sheets exist. Fire-rated type X and moisture-resistant boards are product picks, not this area math. Not a fastening schedule and not code approval.
Use cases
A box-room takeoff of four 12-ft walls, or comparing 10% versus 15% waste. Not a hanging plan.
Limits
No openings field. No ceiling toggle. Estimate only, not structural design. CZNull does not receive the sizes.