How this calculator works
It works out the board area of the room, then how many screws one sheet takes when hung across the framing: one row of screws on every stud or joist the sheet covers, edges included. Walls get a screw every 16″ along each stud and ceilings every 12″ along each joist (metric: 300 mm and 230 mm).
Screws are pro-rated by area, so cut pieces count for less than full sheets. An allowance for dropped and stripped screws is added and the total is rounded up to whole boxes.
screws per sheet = (sheet length ÷ framing spacing + 1) × (sheet width ÷ screw spacing + 1)
4×8 on 16″ framing: 7 × 4 = 28 per wall sheet, 7 × 5 = 35 per ceiling sheet
screws = wall area ÷ sheet area × 28 + ceiling area ÷ sheet area × 35, × (1 + extra)Worked example
A 14′ × 12′ room with 8′ walls, one door and two windows has 365 sq ft of wall and 168 sq ft of ceiling. On 16″ framing a 4×8 sheet takes 28 screws on a wall and 35 on a ceiling, so 365 ÷ 32 × 28 + 168 ÷ 32 × 35 = 503 screws. With 10% extra that is 554 screws, which the list buys as 2 boxes of 300.
Tips before you buy
- Drive screws about ⅜″ (10 mm) in from the edges of the sheet, and never into the edge of a cut.
- Set each screw just below the surface without tearing the paper; a torn screw hole does not hold and has to be re-driven.
- Coarse-thread screws are for wood framing; fine-thread screws are for light-gauge metal studs.
- Use screws long enough to go at least ⅝″ into wood framing: 1¼″ for ½″ board and 1⅝″ for ⅝″ board.
Questions
- How many screws per sheet of drywall?
- A 4×8 sheet hung across 16″ studs takes about 28 screws on a wall and 35 on a ceiling, where screws are spaced closer. A 4×12 sheet takes about 40 on a wall and 50 on a ceiling.
- How far apart should drywall screws be?
- The usual maximum is 16″ apart on walls and 12″ on ceilings along each framing member. Check local code and the board maker’s instructions, especially for fire-rated assemblies, which can call for closer spacing.
- Can I use nails instead of screws?
- Drywall nails are allowed on wood framing, but they are more likely to pop as the framing dries and moves. Screws hold better, need fewer fasteners and are the standard choice for ceilings and metal studs.