How to use this calculator
- Enter Room length in ft.
- Enter Room width in ft.
- Enter Ceiling height in ft.
- Enter Doors.
- Enter Windows.
- Enter Include ceiling.
- Press Calculate. The highlighted row is your order quantity; the note beneath it translates the number into real-world terms.
Formula & constants
Wall area = perimeter × height; add ceiling area; subtract ~21 sq ft per door and 15 per window. Divide by 32 (4×8 sheet) or 48 (4×12), +10% waste. Figure one 4.5-gal mud bucket and one tape roll per 15 sheets. Every default in the fields above is editable — when your supplier’s spec sheet lists a different density, coverage rate or price, enter that number instead. The waste and compaction allowances follow common trade practice; see our methodology page for the derivation of each formula and the standards it references.
Where this fits in the project
Interior finishing runs framing-out: studs, insulation, drywall, then paint and floor coverings. Measure once and reuse the same wall and floor areas across each material takeoff.
How this connects to your project
No quantity stands alone — each material in the chain depends on the ones around it. These are the planning steps that pair with the drywall calculator:
- Paint Calculator — Drywall is primed and painted after installation.
- Insulation Calculator — Insulation is placed behind drywall in walls and ceilings.
- Stud Calculator — Drywall is screwed to wall studs.
- Drywall Cost Calculator — Estimate installation cost from sheet count.
- Baseboard Calculator — Baseboard is installed at the drywall-floor junction.
- Crown Molding Calculator — Crown molding is installed at the drywall-ceiling junction.
- Paint Cost Calculator — Drywall must be primed before painting.
Frequently asked questions
How many sheets for a 12×12 room?
With an 8 ft ceiling and the ceiling boarded: about 16–17 sheets of 4×8 after openings and waste.
4×8 or 4×12 sheets?
4×12 hung horizontally means fewer butt joints and faster finishing — use it wherever access allows carrying them in.
Last verified: — prices reflect current national averages. See our methodology.
Estimates are for planning. Material densities, coverage rates and prices vary by region and supplier — confirm final quantities before ordering, and check local code where structural or electrical work is involved.