CalculateY
Quick Answer
A 12 x 14 foot room with 8-foot ceilings, 1 door, and 2 windows needs approximately 19 sheets of 4x8 drywall for walls and ceiling, plus 280 feet of joint tape and 3.5 gallons of compound.
Enter the width of each wall, separated by commas
Ceiling (leave blank or 0 if not drywalling ceiling)
Common Examples
| Input | Result |
|---|---|
| 8 ft walls: 12, 12, 14, 14 ft, ceiling 12x14, 1 door, 2 windows | 19 sheets (4x8), 13 sheets (4x12), 283 ft tape, 3.0 gal compound |
| 8 ft walls: 10, 10, 10, 10 ft, no ceiling, 1 door, 1 window | 9 sheets (4x8), 6 sheets (4x12), 148 ft tape, 1.5 gal compound |
| 9 ft walls: 15, 15, 20, 20 ft, ceiling 15x20, 2 doors, 4 windows | 33 sheets (4x8), 22 sheets (4x12), 466 ft tape, 4.5 gal compound |
| 8 ft walls: 12, 12, 12, 12 ft, ceiling 12x12, 1 door, 2 windows | 17 sheets (4x8), 12 sheets (4x12), 252 ft tape, 2.5 gal compound |
How It Works
The Formulas
Wall Area = Wall Height x (sum of all wall widths)
Ceiling Area = Ceiling Length x Ceiling Width
Net Area = Wall Area + Ceiling Area - (Doors x 21 sq ft) - (Windows x 15 sq ft)
4x8 Sheets = ceil(Net Area / 32)
4x12 Sheets = ceil(Net Area / 48)
Where:
- Each 4x8 sheet covers 32 square feet (4 ft x 8 ft)
- Each 4x12 sheet covers 48 square feet (4 ft x 12 ft)
- Standard door openings deduct 21 sq ft each
- Standard window openings deduct 15 sq ft each
- ceil rounds up to the next whole sheet
Joint Tape and Compound
Joint tape is needed at every seam where two sheets meet. The estimate uses approximately 12 feet of tape per 4x8 sheet (covering the four edges, shared between adjacent sheets) plus the wall perimeter for corner joints. Joint compound (mud) is estimated at roughly 0.5 gallons per 100 square feet of drywall, covering three coats of mud over all joints and screw holes.
Choosing 4x8 vs. 4x12 Sheets
Standard 4x8 sheets are easier to handle and fit through doorways. 4x12 sheets reduce the number of joints on long walls, resulting in less taping and a smoother finish. For ceilings, longer sheets are preferred to minimize visible joints. For 9-foot and 10-foot ceilings, 4x10 sheets (not calculated here) and 54-inch-wide sheets are also available.
Drywall Types
Standard 1/2-inch drywall is used for most walls and ceilings. Moisture-resistant (green board) or mold-resistant (purple board) drywall is used in bathrooms and laundry rooms. Fire-rated 5/8-inch drywall (Type X) is required for garage walls adjacent to living spaces and certain other applications per building code. All types come in the same sheet sizes.
Worked Example
For a room with 8-foot walls measuring 12, 12, 14, and 14 feet, a 12x14 ceiling, 1 door, and 2 windows: Wall area = 8 x (12 + 12 + 14 + 14) = 416 sq ft. Ceiling area = 12 x 14 = 168 sq ft. Deductions = (1 x 21) + (2 x 15) = 51 sq ft. Net area = 416 + 168 - 51 = 533 sq ft. Sheets (4x8) = ceil(533 / 32) = ceil(16.66) = 17 sheets. Sheets (4x12) = ceil(533 / 48) = ceil(11.10) = 12 sheets. Joint tape = (17 x 12) + 52 = 256 feet. Joint compound = ceil(533 / 100) x 0.5 = 3.0 gallons.