Drywall is bought in sheets but planned in square feet, and the gap between those two units is where the extra trip to the store is born. This drywall calculator takes a wall’s length and height (and how many walls like it), your sheet size — 4×8 or 4×12 — and a waste allowance, and returns the sheet count plus the three supplies people always forget to estimate: screws, ready-mix joint compound and joint tape. The estimating rates are the standard published ones, stated openly under the tool so you can adjust your order with your eyes open.
The rates this calculator uses — stated plainly
Screws: 32 per sheet, the usual count for a 4×8 hung with screws 12 inches apart in the field and 8 inches on the edges; a 4×12 takes proportionally more fixings per sheet, and the calculator scales by sheet count so treat the figure as a floor, not a ceiling. Joint compound: 0.0125 gallons of ready-mix per square foot of wall — the rate behind the common rule that one 4.5-gallon bucket finishes roughly 360–400 square feet across tape coat and two finish coats. Tape: 0.4 linear feet per square foot of wall, matching the widely used 370–400 feet of tape per 1,000 square feet. Waste: 10% is a sane default for cut-outs and damaged corners; hang whole walls with few openings and 5% is enough.
Worked example
One wall, 12 ft long × 8 ft high, 4×8 sheets, no waste: the wall is 96 sq ft, so sheets = 96 ÷ 32 = 3 sheets, screws = 96, compound = 96 × 0.0125 = 1.2 gallons (one 4.5-gallon bucket covers it, with plenty left for repairs), tape = 96 × 0.4 = 38.4 ft (one 250 ft roll). Turn waste to 10% and the sheet count becomes ceil(105.6 ÷ 32) = 4 sheets — that fourth sheet is the difference between finishing on Saturday and driving back on Sunday. Switch to 4×12 sheets and the same wall needs only 2 sheets, but each one is heavier and harder to handle alone.
4×8 or 4×12 sheets?
Bigger sheets mean fewer seams, and seams are where the time goes — taping, mudding, sanding. Pros default to 4×12 on walls they can get them into. Choose 4×8 when the room is up stairs with a turn, when you work alone, or when the ceiling height makes a 12-footer stand-up impossible. The sheet count difference on a typical bedroom wall is one or two sheets; the handling difference is not small.
What is not in the estimate
This is a materials estimator for flat wall area, not a framing or code tool: it does not count studs, corner bead, or the extra mud a wavy old wall drinks, and it assumes you hang the full rectangles you enter. Measure openings honestly — deducting a door from the area but not from your sheet layout is why the waste slider exists. Our Spanish companion tool covers the same job in the pladur system (metric boards, profiles and screws) if your project is specced that way.
Ordering advice
Buy the sheets and tape in one trip, compound by the bucket rather than the box when walls exceed ~300 sq ft, and keep one spare sheet off the floor on battens — drywall stored flat and dry survives to the next project; a sheet leaned damp in a garage does not. Round screws up to the next full box size your store sells; screws are the cheapest insurance on the list.
A note on ceilings
The same calculator prices a ceiling if you enter its length and width as the “wall” — area is area, whatever its orientation. Two adjustments are worth making overhead: choose the waste allowance a notch higher (ceiling cuts around lights and hatches are unforgiving), and remember the screw count assumes wall spacing; ceilings are usually screwed tighter, at 8 inches in the field in many specifications, so treat the screw figure as a minimum there. Compound and tape rates carry over unchanged.
Related tools
Versión en español: Calculadora de Pladur: Placas, Perfiles y Tornillos para Tabiques y Techos de Cartón Yeso · Paint Calculator · Tile Calculator.
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