Drywall calculator
Estimate drywall sheets before ordering panels.
Calculate wall area, subtract openings, add waste, and round up to full drywall sheets for a material-only planning budget.
Room and sheet inputs
Tip: drywall projects also need screws, tape, joint compound, corner bead, sanding supplies, primer, and sometimes moisture-resistant or fire-rated panels.
How this drywall estimate is calculated
The calculator starts with wall area: room perimeter multiplied by wall height, minus the area of doors and windows. It then adds a waste allowance for cutoffs, mistakes, damaged corners, and layout decisions. The adjusted area is divided by sheet coverage and rounded up because drywall is sold as full panels.
Formula: wall area = 2 x (length + width) x height - openings. Area to buy = wall area x (1 + waste rate). Sheets = area to buy / sheet coverage, rounded up.
| Input | Why it matters | Planning note |
|---|---|---|
| Room dimensions | Set the wall surface before openings. | Measure each room separately if heights vary. |
| Openings | Large doors and windows reduce panel area. | Do not subtract tiny openings if they create extra cuts. |
| Sheet size | Changes coverage and seam layout. | 4x8, 4x10, and 4x12 sheets can produce different waste. |
| Waste | Covers cutoffs and handling damage. | Use more for closets, angled ceilings, and many small walls. |