Drywall Sheet Calculator
Calculate exactly how many drywall sheets you need for any project area. Enter your total square footage, choose your sheet size (4×8, 4×10, or 4×12), and set your waste factor — our calculator handles the math so you order the right amount the first time.
How to use this calculator
- Enter your total area in square feet — length × width for each surface.
- Choose your sheet size (4×8 is most common; 4×12 is preferred for ceilings).
- Adjust the waste factor — 10% for simple rooms, 15% for rooms with many cuts.
- Read your sheet count and cost estimate.
How we calculate this
Sheet count is calculated by dividing your total area (in square feet) by the coverage per sheet, then applying your waste factor and rounding up to the nearest whole sheet. A standard 4×8 sheet covers 32 sq ft; a 4×10 covers 40 sq ft; a 4×12 covers 48 sq ft. For example, a 400 sq ft area with 10% waste requires: ⌈(400 × 1.10) ÷ 32⌉ = 14 sheets of 4×8 drywall. Always round up — you cannot install a partial sheet.
What this calculator doesn't include
This calculator estimates sheet count for a flat area only. It does not account for wall layout, ceiling height, or openings (doors, windows). For full room estimates including walls and ceilings, use the Drywall Room Calculator. Joint compound, tape, screws, corner bead, and labor are not included.
Example estimates — Drywall Sheet
Includes 10% waste. Cost estimate at ~$14/sheet (4×8, 1/2" standard) — adjust in the calculator above.
| Area | Sq Ft | 4×8 Sheets | Est. Cost |
|---|---|---|---|
| 10×10 ft | 100 sq ft | 4 sheets | $56 |
| 12×12 ft | 144 sq ft | 5 sheets | $70 |
| 10×20 ft | 200 sq ft | 7 sheets | $98 |
| 16×16 ft | 256 sq ft | 9 sheets | $126 |
| 20×20 ft | 400 sq ft | 14 sheets | $196 |
| 20×25 ft | 500 sq ft | 18 sheets | $252 |
| 20×30 ft | 600 sq ft | 21 sheets | $294 |
| 20×40 ft | 800 sq ft | 28 sheets | $392 |
| 25×40 ft | 1,000 sq ft | 35 sheets | $490 |
| 30×40 ft | 1,200 sq ft | 42 sheets | $588 |
Frequently asked questions
A standard 4×8 sheet of drywall covers 32 square feet. A 4×10 sheet covers 40 sq ft, and a 4×12 sheet covers 48 sq ft. Most residential work uses 4×8 sheets for walls and 4×12 sheets for ceilings (fewer seams). Always add 10% waste to account for cuts around outlets, corners, and openings.
Half-inch (1/2") drywall is standard for most interior walls and ceilings in residential construction. Five-eighths inch (5/8") is used where fire resistance is required — garages, mechanical rooms, and between units in multi-family buildings. 5/8" is also better for ceilings over long spans as it sags less.
10% is standard for simple rectangular rooms. Add 15% for rooms with many doors, windows, or angles. Add 20% for complex spaces with vaulted ceilings, arches, or unusual geometry. It is far cheaper to have extra sheets on hand than to make a second trip to the supply house for one or two sheets.
These are all the same product — gypsum board (gypsum plaster sandwiched between paper facing) is the generic term. Sheetrock is a brand name from USG Corporation that has become commonly used as a generic term, similar to 'Kleenex' for tissues. Drywall is the most common trade term in North America.
Ceiling drywall area equals room length × room width. Use 4×12 sheets for ceilings where possible — the longer sheets span more joists and result in fewer seams to tape. Add 10–15% waste. Ceilings are more difficult to install than walls, so factor in extra material for beginner-level cuts.