Drywall Calculator

How to use the drywall calculator

1. Enter the room's length and width measured along the floor, and the wall height from floor to ceiling.
2. Enter the number of doors and windows. Open Advanced options to change the area deducted for each (20 sq ft per door, 15 sq ft per window by default) if yours are larger.
3. Leave Include ceiling ticked if you are hanging the ceiling too.
4. Pick the sheet size: 4×8, 4×10 or 4×12 ft. Longer sheets mean fewer joints but are heavier to lift.
5. Set the waste allowance. The default 10 % is a common rule of thumb, not a manufacturer figure; raise it for rooms with many corners or cutouts.
6. In Advanced options, choose framing at 16 or 24 in on center for the screw count, and add a price per sheet if you want a cost.

How the calculator works

• Wall area = 2 × (length + width) × height − doors − windows
• Ceiling area = length × width
• Sheets = area × (1 + waste %) ÷ sheet area, rounded up, for walls and ceiling separately
• Joint compound = 10 gal per 1,000 sq ft of board
• Tape = 370 ft per 1,000 sq ft of board
• Screws = sheets × screws per sheet, hung horizontally

Compound and tape use the net board area, without the waste allowance. The 10 gal figure is USG's coverage for Sheetrock Brand All Purpose ready-mixed compound; lightweight, setting-type and topping compounds cover differently, and a higher finish level uses more. The 370 ft of tape comes from USG's paper joint tape data.

Screw count

USG's fastener guidance for screws into wood or steel framing is 16 in apart on walls and 12 in apart on ceilings. A 4×8 sheet hung horizontally over studs 16 in on center crosses 7 framing members; at 16 in spacing that is 4 screws per member on a wall (28 per sheet) and 5 on a ceiling (35 per sheet). At 24 in on center the counts drop to 20 and 25. Fire-rated assemblies follow their tested fastener schedule instead.

Worked examples

Bedroom, 12 × 12 ft with 8 ft walls

One door, two windows, ceiling included, 4×8 sheets and 10 % waste. The walls come to 334 sq ft and the ceiling to 144 sq ft. You need 12 wall sheets and 5 ceiling sheets, 17 in total, plus about 4.8 gal of compound, 177 ft of tape and 511 screws. Switch to 4×12 sheets and the count falls to 8 + 4 = 12 sheets (520 screws).

Living room, 14 × 12 ft with 9 ft walls

Two doors, two windows, 4×12 sheets, 10 % waste. Walls are 398 sq ft and the ceiling 168 sq ft, for 566 sq ft of board: 10 wall + 4 ceiling = 14 sheets, 5.7 gal of compound and 209 ft of tape. Screws: 600 at 16 in on center, or 420 if the framing is 24 in on center. With 4×8 sheets the same room takes 20.

Small room, walls only

A 10 × 8 ft room with 8 ft walls, one door and one window has 253 sq ft of wall: 9 sheets of 4×8 at 10 % waste, or 10 sheets at 15 %.

Reading the result

The sheet count is a purchase estimate, not a cutting plan. Hanging boards vertically, corner bead, closets, soffits, sloped or vaulted ceilings and double-layer or fire-rated assemblies are not modeled. If a wall has a large opening such as a patio door, raise the door area in the advanced options. Once the board is finished, our paint calculator estimates the primer and paint, and our flooring calculator handles the floor.