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Drywall calculator

Enter the room size and ceiling height, and the area of doors and windows.

Enter your numbers to see the result.

Drywall estimating is area divided by sheet size, plus finishing materials. Longer sheets mean fewer seams to tape.

How it works

Wall area = perimeter x ceiling height. Add the ceiling if you are hanging it, take out doors and windows, add extra for cuts, then divide by the sheet area (32, 40 or 48 sq ft).

Example: a 12 x 14 ft room with 8 ft ceilings has 416 sq ft of wall and 168 sq ft of ceiling. Less 40 sq ft of openings, that is 544 sq ft, or 19 sheets of 4x8 with 10% extra.

Mud and tape

USG publishes coverage for its compounds and tape:

  • About 9.4 gallons of ready-mix compound per 1,000 sq ft of board (one 4.5 gal pail per roughly 480 sq ft).
  • About 370 ft of paper tape per 1,000 sq ft.

Texture coats and a Level 5 skim coat use more.

Tips

  • Run sheets horizontally on walls up to 8 ft: two rows of 4 ft sheets usually leave fewer butt joints.
  • Use moisture-resistant board where your code calls for it, such as around tubs and showers.

Sources

Sources last checked 1 November 2026.

Frequently asked questions

How many sheets of drywall for a 12 x 12 room?

With 8 ft ceilings, walls are 384 sq ft and the ceiling 144 sq ft. Take out openings and add 10%, then divide by 32 for 4x8 sheets: roughly 16 to 18 sheets.

How much joint compound per sheet?

At USG’s 9.4 gal per 1,000 sq ft, a 4x8 sheet uses about 0.3 gal.

How much drywall tape do I need?

About 370 ft per 1,000 sq ft of board, per USG.