Drywall Sheet Calculator

Measure the total area of all walls (width × height for each wall), subtract the area of doors and windows, then divide by the coverage area of one drywall sheet. Always add a 10–15% waste factor to account for cuts, mistakes, and odd-shaped areas. Our calculator does all this automatically.

The most common size is 4' × 8' (32 sq ft). Other standard sizes include 4' × 10' (40 sq ft), 4' × 12' (48 sq ft), and 4' × 16' (64 sq ft). In metric regions, 1200mm × 2400mm and 1200mm × 3000mm are standard. Thicknesses typically range from 1/4" to 5/8", with 1/2" being the most common for interior walls.

For a simple rectangular room, 10% waste is usually sufficient. For rooms with many corners, angles, sloped ceilings, or complex layouts, consider 15–20%. Beginners should lean toward 15% to allow for cutting mistakes. Ordering an extra sheet or two is always cheaper than making a second trip to the store.

A standard 4' × 8' sheet typically requires 28–36 screws. Screws should be spaced every 8 inches along edges and every 12–16 inches in the field (center of the board). This translates to roughly 1 screw per square foot. One pound contains approximately 150–200 drywall screws.

As a rule of thumb, you need about 1 gallon of premixed joint compound per 100 square feet of drywall for all three coats (embedding tape + two finish coats). For a single 4' × 8' sheet, budget approximately 0.3–0.5 gallons. A typical 5-gallon bucket covers 400–500 sq ft of installed drywall.

Estimate about 12–16 feet of tape per 4' × 8' sheet, or approximately 0.5 linear feet of tape per square foot of drywall. A standard 500-foot roll of joint tape covers roughly 1,000–1,200 square feet of drywall. Always buy slightly more than calculated to avoid running short mid-project.

Horizontal installation is generally preferred for walls because it reduces the linear footage of seams that need taping, provides better structural bracing, and places the tapered joint at a comfortable working height (about 4 feet). Vertical installation works well for commercial metal stud framing and ensures all edges land on framing members. For ceilings, always install perpendicular to the joists.

1/2-inch drywall is the standard for most interior walls and ceilings in residential construction. It's lighter and easier to work with. 5/8-inch drywall (Type X) is fire-rated and required by code for garages, furnace rooms, and between attached garages and living spaces. It's also used on ceilings with wider joist spacing to prevent sagging. 5/8" boards are about 30% heavier.