Drywall calculator
How many sheets for this room?
Room size in, sheet count out. It measures the walls and ceiling, takes off doors and windows, adds waste, and rounds up to whole sheets.
A door is taken as 3 × 7 ft (21 sq ft) and a window as 3 × 4 ft (12 sq ft). Nothing you enter is saved or sent.
How the count is worked out
Wall area is the distance around the room multiplied by the ceiling height. Ceiling area is length times width. Subtract the openings, divide by the area of one sheet, add waste, and round up, because you cannot buy part of a sheet.
Sheet sizes
| Sheet | Covers | Good for |
|---|---|---|
| 4 × 8 ft | 32 sq ft | Standard 8 ft walls; easiest to carry and to fit in a pickup |
| 4 × 10 ft | 40 sq ft | 9 and 10 ft walls hung vertically, with no butt joint |
| 4 × 12 ft | 48 sq ft | Long walls and ceilings, hung horizontally for fewer seams; needs two people |
How much waste to allow
Ten percent suits a plain rectangular room. Allow 15% or more for rooms with many corners, angled ceilings, soffits or lots of small cut pieces around openings. Some installers do not subtract openings at all on small jobs, since the offcuts from doors and windows are rarely usable; set doors and windows to zero above to see that count.
Turning sheets into a price
The board is usually the smallest part of a drywall quote. Tape, compound, screws, corner bead, delivery to the room, and above all the labour to hang and finish are where the money goes. Count the sheets first, then price the job.
The quantity is sorted. Now price the job.
ScopeBid: Estimate & Invoice is an offline estimate and invoice app for independent service professionals, on iPhone and iPad. Its listing says Profit Guard shows gross margin and markup side by side before a quote is sent, and each quote goes out as a PDF.
Get ScopeBid on the App StoreYour first three quotes are free with full PDFs. ScopeBid Pro is an optional auto-renewing subscription for unlimited quoting and the wider job-costing and invoicing workflow. Check the App Store for current terms.
Honest Little Apps publishes both ScopeBid and this page. This is a separate browser tool and does not sync with the app. App details checked November 10, 2026.
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