Drywall Calculator
Drywall is the most common wall and ceiling finish material in residential construction, sold in 4×8 sheets (32 sq ft each) at standard thicknesses of 1/2" for most walls and ceilings and 5/8" Type X for fire-rated assemblies. Enter room length, width, ceiling height, number of doors and windows, and whether the ceiling needs drywall to get: sheet count with 10% waste for cuts, joint compound buckets (one 4.5-gallon bucket covers about 200 sq ft of finished surface), and drywall tape rolls. Joint compound is applied in three coats (tape coat, fill coat, finish coat) — budget for all three. Hanging drywall horizontally reduces the number of butt joints and is standard for most walls; ceilings are always hung perpendicular to the joists. For ceilings higher than 9 feet, 4×12 sheets are more efficient and reduce butt joints.
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Top Pick1/2" Drywall Sheets — Home Depot~$13.98/sheet* Affiliate links — we may earn a commission at no cost to you.
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How to Use This Calculator
- 1Enter your measurements in the fields above. Use the units shown next to each field (ft, in, etc.).
- 2Click Calculate to get your material estimate instantly.
- 3Review the highlighted result — it shows the key quantity you need to order.
- 4Use Copy Results to save your estimate, or bookmark the URL — your inputs are encoded in the link.
Pro tip: Always add 10% to your material order to account for waste, cuts, and defects.
Frequently Asked Questions
How much drywall do I need for a 12×12 room?
A 12×12 room with 9-foot ceilings has about 360 sq ft of wall area (minus doors/windows) plus 144 sq ft of ceiling = 504 sq ft total. With 10% waste, you need approximately 17 sheets of 4×8 drywall.
What drywall thickness should I use?
Use 1/2" for most walls and ceilings. Use 5/8" Type X in fire-rated assemblies such as garage walls or floors between living units. Use 3/8" only for curved walls or when layering over existing drywall.
How much joint compound do I need per sheet of drywall?
A 4.5-gallon bucket of pre-mixed joint compound covers approximately 200 sq ft of finished wall surface (accounting for three coats and tape). For a 12×12 room with 504 sq ft of drywall, you need about 3 buckets. Lightweight compound is easier to sand; all-purpose compound works for all three coats and is more forgiving for beginners.
Should I use screws or nails for drywall?
Screws are strongly preferred. Drywall screws hold better than nails, don't pop as easily with seasonal wood movement, and allow precise depth control with a drywall screw gun. Use 1-5/8" coarse thread screws for 1/2" drywall on wood framing, 1-1/4" fine thread for metal framing. Space screws every 12 inches on the field and 8 inches on the edges.