Drywall Calculator
Calculate how many drywall sheets you need for your walls including waste factor.
How many sheets of drywall do I need?
Calculate wall area: 2 x (Length + Width) x Height. Divide by sheet size (standard 4x8 = 32 sq ft). Add 15% waste for cuts, mistakes. Example: 20'x15' room, 8' ceilings = 2 x (20+15) x 8 = 560 sq ft / 32 = 17.5 sheets, with waste = 21 sheets. Ceiling needs additional sheets (L x W / 32). Don't forget to subtract large openings (doors, windows) but keep waste factor for accuracy.
What size drywall sheets should I use?
Common sizes: 4x8 (standard, easiest to handle), 4x10 (reduces seams, 10' ceilings), 4x12 (fewer seams, harder to hang). Thickness: 1/2" (walls, standard), 5/8" (ceilings, fire-rated), 1/4" (curved surfaces). For DIY, 4x8 sheets are easiest. Professionals prefer longer sheets (fewer seams to tape). Horizontal hanging reduces seams but requires help. Always hang perpendicular to studs for strength.
How much joint compound and tape do I need?
Estimates per 1,000 sq ft of drywall: Joint compound: 60-80 lbs for taping, 50-70 lbs for each additional coat (3 coats total = 160-220 lbs). Paper tape: 370-400 linear feet. Screws: 1 lb per 5 sheets. Corner bead: Linear feet of outside corners. Example: 20 sheets (640 sq ft) needs ~100-140 lbs compound, 240-260 ft tape. Buy extra - better to have leftovers than run out mid-project.
Should I hang drywall vertically or horizontally?
Horizontal (perpendicular to studs) is stronger and code-preferred: Fewer seams (one across middle instead of multiple vertical), spans studs for better support, easier to hide seams at comfortable height. Vertical hanging: Easier for DIY (can hang alone), less lifting, good for rooms under 8' or when height matches sheet. Commercial/professional always horizontal. For 8' walls with 4x8 sheets, horizontal is standard and reduces taping work by ~25%.