Drywall Calculator

How Much Drywall Do I Need?

1. Walls: perimeter × wall height, minus doors and windows.
2. Ceiling: length × width.
3. Sheets: divide each by the sheet area (32 sq ft for 4 × 8, 40 for 4 × 10, 48 for 4 × 12), add about 10%, and round up.

Worked example. A 12 × 10 ft room with 8 ft walls has 352 sq ft of wall. Take off one door (20 sq ft) and two windows (15 sq ft each) and 302 sq ft is left. With 10% extra that’s 11 sheets of 4 × 8 for the walls, and 5 more for the 120 sq ft ceiling.

Screws, Mud, and Tape

• Screws: USG’s recommended spacing for non-fire-rated work is 16 in on walls and 12 in on ceilings. On framing 16 in on center, that’s about 28 screws per 4 × 8 sheet on walls and 35 on ceilings. Fire-rated assemblies have their own fastening schedules.
• Joint compound: about 1 gallon per 100 sq ft (HomeGuide). The worked example needs about 4.2 gallons.
• Tape: about 10–16 ft per 4 × 8 sheet (HomeGuide), so 160–256 ft for 16 sheets.

Which Sheet Size?

Longer sheets mean fewer seams to tape and finish, which saves time and gives a better wall. The catch is handling: a 4 × 12 sheet is heavy and awkward to get through doors and up stairs. Many DIYers use 4 × 8 sheets on walls and longer sheets where they can on ceilings, often with a rented drywall lift.

What It Costs

HomeGuide gives these figures: sheets about $10–$20 each; hanging and finishing labor $1.00–$2.70 a sq ft; installed $1.50–$3.50 a sq ft on walls. The smoother the finish (level 4 or 5), the more it costs.