Drywall Calculator: Walls, Ceilings & Sheets

Estimate drywall sheets for rectangular walls and ceilings, or enter an area you already measured. Use actual sheet dimensions and your own allowance for cuts and waste.

Estimate sheets needed

MeasurementsWhat are you covering?Room length (ft)Room width (ft)Wall height (ft)Total wall openings (sq ft)Known area to cover (sq ft)Actual sheet width (ft)Actual sheet length (ft)Include the ceiling?Waste allowance (%)Price per sheet ($, optional)

Feet presets: 4 x 8, 4 x 10, or 4 x 12 sheets: change the actual sheet length to 8, 10, or 12. Metric defaults are 1.2 x 2.4 m. Verify your product dimensions. Changing measurement systems clears room dimensions and resets sheet dimensions.

Openings apply only to walls, not the ceiling. Blank openings count as zero. Waste starts at 0%: choose your own allowance (0-50%) based on the project. The same sheet size is used for all surfaces.

Enable JavaScript to calculate. Manually, divide each surface area including your waste allowance by one sheet's area, then round up separately for walls and ceiling.

How the estimate works

Rectangular wall area = 2 x (room length + room width) x wall height, minus your total wall openings. Flat ceiling area = length x width. Each included surface group is multiplied by (1 + waste percentage / 100), divided by sheet area, and rounded up to whole sheets.

Example: a 12 x 10 ft room

At 8 ft high with 32 sq ft of wall openings, net wall area is 320 sq ft. A 120 sq ft ceiling adds to that. With 4 x 8 ft sheets and 10% waste, walls need 11 sheets and the ceiling needs 5, for 16 sheets total. At $15 per sheet, the sheet-only estimate is $240.

What is excluded?

No allowance is automatically made for double layers, sloped ceilings, curved walls, closets, or other rooms. Use known area for a separately measured surface. This tool does not select drywall thickness, fire rating, fasteners, framing, or installation methods. Follow product instructions and applicable local requirements.

Does the optional cost include installation?

No. It multiplies the estimated whole-sheet count by your price per sheet. It excludes labor, delivery, tax, screws, tape, and compound unless already included in that sheet price.