How this calculator works. Wall area = perimeter × height; openings are not subtracted for doors and windows under standard practice (you cut them out of full sheets, and the cutouts are mostly waste), but we credit half a standard opening each to stay realistic. We add your waste factor, divide by sheet area, and round up.
Consumables use standard trade figures: about 32 screws per 4×8 sheet (12" field spacing) and roughly one gallon of ready-mix joint compound per 100 sq ft of board for a three-coat finish.
How many sheets of drywall?
Drywall estimating is deliberately generous: you can't stretch a sheet that's two inches short, and seams you create from offcuts cost more in tape and mud than the board you saved. The professional habit is simple — compute the area, add 10%, round up, and orient sheets to minimize seams (horizontally on walls, with the long edge across studs).
Sheet size matters more than beginners expect. A 4×12 sheet on an 8-foot wall creates one fewer vertical seam per 12 feet than 4×8 sheets — and every seam avoided is 20 minutes of taping and sanding you skip. Use the biggest sheets you can physically carry into the room.
What else goes in the cart
| Item | Per 500 sq ft of board |
|---|---|
| Drywall screws (1-1/4" coarse) | ≈1 lb per 300 sq ft — one 5-lb box covers most rooms |
| Joint tape | ≈370 ft (one 500-ft roll) |
| Ready-mix joint compound | ≈one 4.5-gal bucket |
| Corner bead | Measure your outside corners in linear ft |
Buying tips
Use 1/2" regular board for walls, 5/8" Type X where fire code requires (garages, near furnaces), and moisture-resistant board in bathrooms — but cement board, not drywall, behind tile in wet areas. Have sheets delivered; ten sheets of 4×8 weigh over 500 lbs and won't fit in an SUV.
Common questions
Do I subtract doors and windows?
Mostly no — that's standard practice. Openings get cut from full sheets and the offcuts are rarely reusable. Our formula credits a modest allowance so large window walls aren't overestimated.
Screws or nails?
Screws, always. They don't pop, they're adjustable, and a drywall screw gun or drill with a dimpler bit sets them perfectly. Nails are only used for temporarily tacking.
How much mud for skim coating?
Skim coating (level-5 finish) roughly doubles compound usage — plan a gallon per 50 sq ft instead of 100. For texture, check the product's own coverage chart; it varies wildly.
Can one person hang drywall?
Walls, yes — slowly. Ceilings, rent a drywall lift (~$40/day); it pays for itself in the first three sheets and your neck will agree.