Drywall for a 9 × 12 ft room
With 8 ft ceilings, the walls are 336 ft² and the ceiling 108 ft². Sheet counts include 10% waste; supplies are rules of thumb.
| What you hang | Area | 4×8 sheets | 4×12 sheets | Joint compound | Joint tape |
|---|---|---|---|---|---|
| Walls only | 336 ft² | 12 | 8 | 3.4 gal | 124 ft |
| Walls and ceiling | 444 ft² | 16 | 11 | 4.4 gal | 164 ft |
| Ceiling only | 108 ft² | 4 | 3 | 1.1 gal | 40 ft |
Hanging tips
Hang the ceiling first, then the walls, running sheets horizontally. Stagger the joints, use about one screw per square foot, and tape and mud every seam in three coats. Use moisture-resistant board in bathrooms and fire-rated (5/8 in Type X) in garages and next to furnaces. See the drywall calculator to adjust for your ceilings.
Hauling, studs and screws
A ½ inch 4 × 8 sheet weighs about 55 lb, so the 16 sheets for the walls and ceiling weigh roughly 880 lb (0.44 tons). Most pickups can take a few sheets flat, but a full order is a delivery, or several trips. Carry them on edge, and use a helper.
The walls are 42 ft around, which is about 36 studs at 16 inch centers (the corners add a few). Plan on roughly one screw per square foot, which is 512 screws for this order.
A 9 × 12 room: a good case for 12 ft sheets
A 9 × 12 room takes 16 sheets of 4 × 8 for the walls and ceiling with 8 ft ceilings, or 11 sheets of 4 × 12.
Twelve-foot sheets cover each long wall in two horizontal courses with no butt joints, and three of them span the ceiling the same way with only the tapered edges to tape. They are heavy and awkward on stairs, so measure the route in before you order. With 4 × 8 sheets the job is 880 lb of board, and the ceiling uses about 3.4 sheets' worth of area.
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Tools & materials for this project
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Frequently asked questions
How many sheets of drywall for a 9x12 room?
16 sheets of 4 × 8 ft for the walls and ceiling with 8 ft ceilings and 10% waste, or 12 for the walls only. With 4 × 12 ft sheets it is 11 for both.
How much joint compound for a 9x12 room?
About 4.4 gallons for the walls and ceiling as a rule of thumb (1 gallon per 100 ft²), so one 4.5 gallon box is enough.
Do I subtract windows and doors for drywall?
Not usually. The cut-outs are offset by the waste allowance, and you need the cutoffs for filling around openings.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.