Crunch the numbers before you build.
Calculate sheets, joint compound, tape, and screws for any room. Enter your dimensions once — get your full material list.
By BuildCrunch Team · Last updated July 17, 2026
A 12×14 ft room with an 8 ft ceiling (1 door, 2 windows) needs 19 sheets of 4×8 drywall — about 593 sq ft of coverage including the standard 10% waste factor.
We calculate wall area (perimeter × height) and, if selected, ceiling area (length × width), then subtract standard deductions for doors (21 sq ft) and windows (12 sq ft).
Your waste percentage is added to that net area, and sheets needed = total area ÷ sheet size (32 sq ft for 4×8, 48 sq ft for 4×12), always rounded up since you can't buy a partial sheet.
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Standard ½-inch drywall runs $12-$18 per 4×8 sheet. Moisture-resistant (green board) costs $14-$22. Fire-rated (Type X) runs $15-$25. Prices vary by region and availability. For a full room, materials typically cost $0.40-$0.65 per square foot before labor.
Plan for about 28-32 screws per 4×8 sheet. Screws should be placed every 8 inches along edges and every 12 inches in the field (center of the sheet). Use #6 × 1⅝-inch coarse-thread screws for wood studs, or fine-thread for metal studs.
Budget about 1 gallon of pre-mixed compound per 100 square feet of drywall. A standard 4.5-gallon bucket covers roughly one average-sized bedroom. You'll apply three coats — taping coat, filler coat, and finish coat — with sanding between each.
Use ½-inch for most walls and ceilings with joists 16 inches on center. Use ⅝-inch for ceilings with 24-inch joist spacing to prevent sag. Use ¼-inch for curved walls. Use moisture-resistant board in bathrooms and Type X fire-rated board for garage walls and ceilings adjacent to living spaces.
Yes. Factory (tapered) edges are pre-beveled so the tape and compound sit flush, but they still need taping — skipping it leaves a visible seam once painted. Butt joints (cut, non-tapered edges) need extra care since there's no built-in recess; expect to feather the compound 12-16 inches wide on those to hide the joint.
10% is standard for a simple rectangular room with average cuts around doors and windows. Bump to 15% for rooms with lots of corners, angled ceilings, or electrical box cutouts, since more cuts mean more scrap. Closets and small bathrooms often run higher percentage-wise simply because the room is small relative to the waste from a single sheet.