Drywall Estimator
Enter the total area to cover — the estimator adds 10% cutting waste and counts screws and joint compound.
Runs entirely in your browser — your numbers never leave this page.
How it works
Drywall estimating starts with total area, then converts to sheets, fasteners, and mud. The 10% waste covers cutouts for outlets, windows, and the strips that don't divide evenly:
Sheets = ceil(Area ÷ sheet area × 1.10)
Screws ≈ sheets × 32
Joint compound ≈ 1 gallon per 100 sq ft (a 5-gal bucket covers ~500 sq ft)
- 4×8 sheets (32 sq ft) fit through doors and are manageable solo. 4×12 sheets (48 sq ft) mean fewer seams but need two people and clear access.
- Hang sheets horizontally on walls — the long tapered edges meet at 4 ft height, which is the easiest seam to finish, and you get fewer butt joints.
- Screw pattern: every 12 in along studs for walls, every 12 in (5/8-in board) on ceilings — about 32 screws per 4×8 sheet.
- Thickness: ½-in for most walls, ⅝-in for ceilings (it resists sagging between joists) and for fire-rated garage walls.
- Don't forget joint tape (~one 500-ft roll per 500 sq ft) and corner bead for every outside corner.
Frequently asked questions
Should I buy 4×8 or 4×12 drywall sheets?
4×8 sheets are easier to carry, fit through doorways, and one person can hang them. 4×12 sheets leave fewer seams to tape but need two people and a clear path. For most DIY rooms, 4×8 wins on handling.
½-inch vs ⅝-inch drywall — which do I need?
½-in is standard for walls. Use ⅝-in on ceilings (it won't sag between joists) and on garage walls shared with the house, where fire code usually requires the thicker Type X board.
How many screws per sheet of drywall?
About 32 per 4×8 sheet — screws every 12 inches along each stud for walls. Ceilings get the same 12-in spacing with ⅝-in board. Buy coarse-thread screws for wood studs, fine-thread for metal.
How much joint compound do I need?
Roughly 1 gallon per 100 sq ft of drywall for three coats. A 5-gallon bucket covers about 500 sq ft — this estimator converts your area into buckets automatically.
Why add 10% waste?
Outlet and switch cutouts, window openings, and narrow strips at the end of walls all consume full or partial sheets. 10% covers a normal room; go 15% for rooms with lots of windows or angled walls.
Do I hang drywall vertically or horizontally?
Horizontally on walls. The 4-ft tapered edge lands at a comfortable working height for taping, and you get half as many butt joints (the hard seams) as vertical hanging.
What is the green / purple drywall for?
Moisture-resistant board (green, or purple XP) goes in bathrooms, kitchens, and laundry rooms. It is not waterproof — behind tile in a shower, use cement backer board instead.
How do I estimate drywall for one room?
Measure each wall (width × height) and add them up, then add the ceiling (length × width). Example — a 12×12 ft room with 8-ft ceilings: four walls of 12 × 8 = 384 sq ft of wall, plus a 144 sq ft ceiling = 528 sq ft total. Enter that in the estimator.
How much joint tape do I need?
About one 500-ft roll per 500 sq ft of drywall. Paper tape is cheapest and strongest for flat seams; mesh tape is easier for beginners but needs setting-type compound to avoid cracking.
Can I hang drywall over old plaster or paneling?
Yes, if the old surface is solid — screw through it into the studs with longer screws (1-⅝ in). If the old wall is crumbling or wavy, tear it out; drywall telegraphs every bump underneath.