Drywall Sheet Calculator
Drywall sheets = area ÷ sheet area, rounded up to whole sheets, plus a cut allowance. A 4 × 8 sheet covers 32 ft², so 640 ft² of wall and ceiling takes 20 sheets, or 22 with 10% waste. For screws, joint compound and tape as well, use the Drywall Calculator.
How it's calculated: Sheets = area ÷ sheet area (32, 40 or 48 ft²), rounded up, plus the waste allowance.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Sheets = Area ÷ sheet area, rounded up, plus a waste allowance
Run the calculation to see each step with your own numbers.
640 ft² of wall and ceiling, 4×8 sheets, 10% waste.
640 ÷ 32 = 20 → order 22 sheets
- Gross area; openings are not deducted.
- Whole sheets — a partial sheet is a full purchase.
- Need mud and screws too?
- Use the full Drywall Calculator — it adds screws, joint compound and tape.
- Which sheet length should I buy?
- Longer sheets mean fewer butt joints, which are the hardest to finish flat, so pros use 12 ft sheets on long walls. But they're heavy and hard to manoeuvre in tight rooms or up stairs. All three lengths give the same total coverage.
- How many sheets of drywall do I need?
- Divide the area to board by the sheet size — 32 ft² for 4 × 8, 40 for 4 × 10, 48 for 4 × 12 — round up, then add about 10% for cut-offs. 640 ft² of 4 × 8 board is 20 sheets, or 22 ordered.
- How many 4×12 drywall sheets cover 640 square feet?
- About 13⅓, so 14 whole sheets before the waste allowance — fewer sheets than 4 × 8 for the same area, and fewer butt joints to finish.
Sheet size
Standard 4×8 ft panel = 32 ft². Nominal panel size (drywall ASTM C1396, plywood/OSB PS 1 / PS 2).
About the Drywall Sheet Calculator
The Drywall Sheet Calculator gives just the number of gypsum board sheets for a wall or ceiling area, for when you already have the fasteners and finishing materials. Pick the sheet size — 8, 10 or 12 ft — and it rounds up to whole sheets plus a cut allowance. For screws, joint compound and tape as well, use the full Drywall Calculator.
What you enter
- Area to board
- Sheet size
- Waste allowance — Cut-offs. 10% typical.
What you get back
- Sheets — shown as the exact figure and, separately, a recommended figure with your waste allowance added.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Drywall Calculator — Drywall sheets, screws, mud and tape for a room.
- Plywood Calculator — Sheets of plywood or OSB for a floor, wall or roof area.
- Wall Square Footage Calculator — Wall area for one or more walls, with openings deducted.
Related articles
- Drywall vs Drywall Sheet: Understanding Material Quantities — 'Drywall' and 'drywall sheets' usually refer to the same material — the distinction that matters is sheet size and how area converts to a sheet count.
Part of the Drywall & Insulation calculators.