Drywall Sheet Calculator
Calculate how many drywall sheets a room needs, with openings deducted, plus screws, joint tape, compound and corner bead quantities and an estimated material cost.
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Sheet count is not area divided by sheet size
Drywall is sold in fixed sheets, and a wall four hundred millimetres wider than two sheets still needs a third sheet cut down. The offcut is often unusable because the cut edge has no tapered edge to receive tape, so the waste is real rather than recoverable. Estimating by area alone consistently comes up short, which is why the usual advice is to add ten to fifteen percent, an adjustment that is really compensating for the sheet geometry being ignored.
Deducting openings has a threshold
Small openings should not be deducted at all. A single door in a wall does not save a sheet, because the sheet still has to be bought and cut around the opening, and the cut piece is rarely large enough to use elsewhere. The common rule is to ignore openings under about two square metres and deduct larger ones such as a patio door or a picture window. Deducting every small opening is how an estimate ends up short.
Everything else scales from the sheet count
Screws run at roughly thirty two per sheet for walls at four hundred millimetre stud centres and more for ceilings. Joint tape follows the linear metres of seam, which is a function of how the sheets are laid out rather than the area. Joint compound is usually estimated per sheet, around half a bucket per ten sheets across three coats. All of it is calculated here so the shopping list is complete rather than a sheet count plus a guess.
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Frequently Asked Questions
Should I hang drywall horizontally or vertically?
Horizontally on walls under about 2.7 metres, since it puts the tapered seam at a comfortable working height and shortens the total seam length. Vertically where walls are taller or where the studs are out of line. The tool reports seam length for both.
Do I deduct doors and windows?
Only the large ones. Openings under about two square metres do not save a sheet in practice because the sheet is still bought and cut. Deducting every small opening is the most common reason an estimate falls short.
How many screws per sheet?
About 32 for a wall sheet at 400 millimetre stud centres, and about 40 for a ceiling where the fixing pattern is tighter. Buy by weight: a thousand 32 millimetre drywall screws is roughly 2.7 kilograms.
How much joint compound will I need?
Roughly one 20 kilogram bucket per twelve to fifteen sheets across three coats, more if the finish level is high or the framing is uneven. Setting compound for the first coat and lightweight for the finish is the usual combination.
What thickness should I use?
12.5 millimetre, or half an inch, is standard for walls and ceilings at 400 millimetre centres. Use 15 millimetre for ceilings at 600 centres or where fire rating requires it, and moisture resistant board in bathrooms.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Enter room dimensions, deduct door and window openings, and get a full drywall material list.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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