This calculator estimates drywall or plasterboard sheets for a room's walls and, when selected, its ceiling. Use it once room dimensions and board size are known, before planning delivery or comparing a hanger's materials list. It does not count screws, adhesive, joint tape, compound, corner bead, insulation, framing, fire-rated layers, moisture-resistant boards, or labour. US mode defaults to 4 × 8 ft sheets, while UK mode uses 1200 × 2400 mm boards; choose the actual size stocked for your job where the tool allows. Board orientation and full-sheet delivery access affect real waste, so give the result to your drywall supplier or installer and ask them to confirm sheet size, type, number of layers, and finishing materials.
How this is calculated
Wall area is the room perimeter times ceiling height: 2 × (length + width) × height. The ceiling is the floor rectangle. Openings are not deducted because offcuts from doors and windows rarely equal a full sheet, and leftover pieces are useful for soffits and patches.
Sheets are sold in fixed sizes. Dividing total area by one sheet and rounding up is how suppliers count an order. A waste allowance covers miscuts and damaged boards.
Area alone cannot optimise every seam. Horizontal or vertical hanging, stud spacing, ceiling joists, and whether long sheets can reach the room all affect the practical board schedule.
Multi-layer fire or acoustic assemblies need the calculated sheet count for each layer. Confirm board type and fixing pattern with the specified system rather than multiplying a standard-room order blindly.
Formula & methodology
Wall area = 2 × (Length + Width) × Height. Ceiling = Length × Width (if included). Total with waste = (walls + ceiling) × (1 + waste %). Sheets = Total ÷ sheet area, rounded up.
Worked example
A 16 ft × 12 ft room, 8 ft ceilings, walls and ceiling, 10% waste, 4×8 sheets
1.Wall area = 2 × (16 + 12) × 8 = 448 ft²
2.Ceiling = 16 × 12 = 192 ft²
3.Gross = 640 ft²; with 10% waste = 704 ft²
4.Sheet area = 32 ft²; 704 ÷ 32 = 22 sheets
Calculator
Enter your dimensions below. Results update as you type. Costs are planning ranges — confirm with a local supplier before you order.
Room dimensions
ft
ft
ft
Add cost details
%
10% is typical; use 15% for rooms with lots of openings
$
Results
Sheets to order
22
4×8 ft sheets, including 10% waste
Coverage with waste
704 ft²
Estimated material cost
$308
Sheets only — joint compound, tape, screws, and corner bead are extra. Door and window openings are not deducted; leftover offcuts usually cover those gaps.
Frequently asked questions
Should I deduct doors and windows?
You can mentally subtract large openings, but most hangers still round up to full sheets. This calculator does not deduct openings so you are less likely to run short.
What sheet size does this assume?
US: 4×8 ft (32 ft²). UK: 1200×2400 mm. If you are hanging 4×12 ft boards, you will need fewer sheets for the same area — divide the coverage figure by 48 ft² instead.
Does this include joint compound and tape?
No — only boards. Compound, tape, screws, and corner bead depend on the finish level (typically 3–5) and should be listed separately.
How much waste should I add?
Ten percent is reasonable for a rectangular room. Use 15% if there are many corners, arched openings, or you are hanging for the first time.
Last updated 2026-08-01. Formulas are planning methods — confirm with a supplier before you order. See how we calculate and the disclaimer.