Drywall Calculator
Room dimensions in — sheet count out, plus the mud, tape and screws the finishing pass actually consumes.
The short answer
Formula. Sheets = wall area × (1 + waste) ÷ sheet area (a 4×8 sheet covers 32 sq ft); finishing per sheet runs about 0.32 gal mud, 16 ft of tape, 36 screws.
Example. A 12×12×8-ft room (384 sq ft of wall) in 4×8 sheets at 10% waste takes 14 sheets, about 4.5 gallons of joint compound and 224 ft of tape.
How this calculator works
Sheets come from area. The wall area of a rectangular room is perimeter × height — a 12 × 12 room with 8 ft walls is 48 ft around × 8 ft = 384 sq ft. Subtract 20 sq ft per door and 15 per window (keep the deductions even if the offcuts around a door are only partly reusable — that is what waste absorbs), add the ceiling's length × width if you are boarding it, inflate by the waste factor, and divide by the sheet's square footage: 32 for the standard 4 × 8, 40 for 4 × 10, 48 for 4 × 12. Round up — the supplier sells whole sheets, and your waste factor assumed you would need the margin.
The finishing supplies are rules of thumb, deliberately editable because tapers argue about them. Mud: about 0.32 gallons of all-purpose compound per 4 × 8 sheet for tape plus two coats — the industry's "one gallon per 100 sq ft." Tape: about 16 ft per sheet, since each sheet contributes a shared 8-ft tapered joint and butt ends. Screws: roughly 36 per sheet at 12 in on edges and 16 in the field; drywall screws sell by the pound (roughly 300 to 320 per pound for 1-1/4 in coarse), so a 4.5-lb box comfortably covers a room like our 14-sheet example.
Where pros save money and DIYers do not: sheet orientation and butt joints. Hanging 4 × 8 sheets horizontally on 8 ft walls minimizes seam length; on 9 or 10 ft ceilings, buying 4 × 10 or 4 × 12 sheets vertically removes butt joints entirely — the flat, hard-to-hide joints every 8 ft — which is why the sheet-size selector exists. Half-inch board is the interior-wall standard; go 5/8 in type X where code demands fire rating (garage ceilings, shared walls), and green/purple board in bathrooms. And mud math assumes three passes: tape coat, fill coat, skim — the skim is what makes flat-five walls, and it is the pass that quietly doubles mud use if you are perfectionist.
Sources & review date
- Finishing quantities per sheet (0.32 gal mud, 16 ft tape, 36 screws) are typical published trade figures — editable inputs on the page.
Last reviewed: October 2026. Numbers that drift (fees, prices, densities) are editable inputs on this page.
Drywall FAQs
How many 4x8 drywall sheets do I need for 1000 square feet?
1,000 sq ft with 10% waste is 1,100 sq ft ÷ 32 sq ft per sheet = 35 sheets (34.4 rounded up). Add one or two for luck on big jobs; returns are easy.
How many pounds of screws do I need per sheet of drywall?
At ~36 screws per sheet and ~300 screws per pound, figure about 0.12 lb per sheet — call it 1 lb per 8 sheets. A 5-lb box does a 35-sheet job with spares.
How many coats of mud does drywall need?
Three is standard: the tape coat (bedding the tape), the filler coat over it, and a skim/finish coat feathered wide. The 0.32 gal/sheet rule covers all three at average skill; beginners trowel more off the knife and back into the pan.
Does this work for hanging drywall on a ceiling?
Yes — include the ceiling and the area math is identical (length × width of the room). Note that ceilings want 5/8-in board or 24-in framing blockers: sag is real, and thinner board on 24-in centers waves visibly under recessed lighting.