Sheet count, compound, tape, screws — the full mudding kit.
Based on the dimensions on the left — edit them to match your project and this updates as you type.
17 sheets — includes 10% waste for cuts
Tip: Order delivery for large quantities. Carrying drywall through doorways is how backs get hurt.
4 boxes — 1-1/4" for 1/2" board, coarse thread for wood studs and fine thread for metal
2 buckets — for taping, topping, and final coats
Tip: Apply 3 thin coats, not 1 thick one. Sand lightly between coats.
5 rolls — paper tape is stronger than mesh for seams
Tip: Embed tape in wet mud, then scrape flat — no bubbles.
Protects every outside corner — required for a clean finish
Wet sponge for detail, pole sander for flats — get both
Prime before painting — raw drywall soaks paint unevenly
Straight cuts across full sheets — worth every penny
Sets screws to the right depth without tearing paper — get the dimpler bit
Don't forget
Rent a drywall lift for ceilings. Holding a 70 lb sheet overhead while screwing it in is how injuries happen. HD rents lifts for about $50/day.
Drywall has tapered long edges — a shallow recess milled into the face so that tape and compound sit flush instead of proud. Seams along those edges disappear with a normal three-coat finish. The cut ends have no taper. Butt two of them together and you have a seam standing proud of the surface, which has to be built up on both sides and feathered out 16 to 24 inches to become invisible under a raking light.
That is the whole argument for long sheets. A 4 × 12 board spans most residential walls in one piece and gives you zero butt joints. Two 4 × 8 sheets on the same wall give you one, plus the hour of feathering and sanding that goes with it. Hanging horizontally — the long edge running across the studs — also puts the tapered seam at a comfortable 4 ft working height instead of running vertical seams floor to ceiling.
This calculator works in 32 square feet per sheet, the 4 × 8 size, because that is what fits in a vehicle and what two people can carry up a stairwell. If you are having board delivered, ask for 12-footers and divide the square footage by 48 instead.
Thickness does not change the sheet count, only the weight and the price. A 4 × 8 sheet of 5/8 runs noticeably heavier than 1/2, which is worth knowing before you plan a ceiling as a two-person job.
This calculator subtracts 20 square feet per door and 15 per window, which is the right way to estimate the finished surface. It is not how the board gets used. Almost nobody cuts a sheet to fit around a door before hanging it — you hang straight over the opening, screw off the field, then run a saw around the frame from behind. It is faster, the edges land exactly on the opening, and the cut-out is usually scrap.
So treat the deduction as an estimate of area, not of sheets saved, and leave the 10 percent waste factor alone. Raise it to 15 percent if the room has a lot of angles, a stairwell, a vaulted ceiling, or more openings than a normal bedroom — those are the jobs where offcuts pile up faster than you can use them.
Walls and ceiling, 8 ft ceiling height, one door and one window, 10 percent waste included. Every figure is this page's own formula applied to the stated room.
Measure the perimeter of the room, multiply by the ceiling height for wall area, add length × width if you are boarding the ceiling, then subtract the openings. Divide by 32 for the number of 4 × 8 sheets, or by 48 for 4 × 12 sheets, and add about 10 percent for waste. A 12 × 12 ft room with an 8 ft ceiling, one door and one window comes to roughly 493 square feet including the ceiling, which is 17 sheets of 4 × 8.
About 17 sheets of 4 × 8 board, boarding the walls and the ceiling with an 8 ft ceiling height, one door and one window. That is 349 square feet of wall plus 144 of ceiling, divided by the 32 square feet in a sheet, plus 10 percent waste. Walls only, with no ceiling, drops it to 13 sheets.
Buy the longest sheet you can physically get into the room. Drywall has tapered long edges that form a shallow trough for the compound to fill, so those seams finish nearly flat. The cut ends have no taper, and a seam between two of them — a butt joint — has to be built up and feathered wide to hide. A 4 × 12 sheet spans most residential walls in one piece and removes butt joints entirely. 4 × 8 is the DIY default because it fits in a car and two people can carry it, and it is what this calculator assumes at 32 square feet per sheet.
Half-inch is the residential standard for walls and is what most rooms need. Five-eighths Type X is the one to use where fire resistance is required — the garage side of a garage-to-house wall and its ceiling is the common case in the US residential code — and on ceilings where the framing is 24 inches on centre, because half-inch board will sag between joists over time, especially with insulation sitting on it. Check your local code before deciding, since fire-separation requirements vary. Three-eighths and quarter-inch exist for patching and for curved walls, not for general hanging.
The usual spec is a screw every 16 inches along each framing member on walls and every 12 inches on ceilings, which works out to roughly 32 screws in a 4 × 8 wall sheet. Length follows the board thickness, because the screw has to bite at least 5/8 inch into the framing: 1-1/4 inch for 3/8 and 1/2 inch drywall, 1-5/8 inch for 5/8. Coarse thread in wood framing, fine thread in steel studs. This calculator allows one box per five sheets, which leaves margin for the ones you strip, overdrive through the paper, or drop.
Paper tape is stronger in tension and is the right choice for flat seams and inside corners, where it also gives you a crease to fold against. Self-adhesive mesh is faster to put up and does not need bedding compound under it, but it is weaker, so it needs a setting-type compound over it rather than a premixed all-purpose — premixed does not develop enough strength to stop a mesh seam cracking. If you are taping your first room, paper on the flats and corners is the more forgiving option.
This calculator allows one bucket per 400 square feet of board, which covers a normal three-coat finish — a bedding coat over the tape, a fill coat, and a thin skim. Buy setting-type compound as well if you have deep gaps or butt joints to build up: it hardens by chemical reaction rather than by drying, shrinks less, and lets you put a second coat on the same day.
Written and maintained by the BuildGuiders team. Quantities use standard sheet sizes and trade coverage rates; fire-rating and framing requirements come from the US residential code and vary locally, so confirm yours before you buy. Product recommendations are researched and compared against manufacturer specifications and verified buyer feedback — we do not test drywall.