Construction & DIY
Drywall Calculator
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How to use it
Using the drywall calculator
- 01
Compute total area
Wall length × ceiling height summed over all walls (plus ceiling area if boarding overhead).
- 02
Round up to sheets
The calculator rounds to whole 4×8 boards; offcuts become closet patches and soffit fills.
- 03
Buy screws by weight
Match the pound estimate to coarse-thread screws for wood studs or fine-thread for metal.
Good to know
Sheets, not square feet, at the counter
Drywall is sold by the board, which is why this tool rounds up rather than quoting fractional sheets. Openings like doors technically reduce area, but their offcuts rarely fit elsewhere; experienced hangers buy the gross number.
When bigger boards pay off
Fewer seams mean less taping, sanding and dust. If your walls exceed 8 feet, 4×10 or 4×12 boards eliminate a horizontal joint across the room; harder to handle alone but dramatically better finished results.
Screws are cheap; failures are not
Under-driven or missing screws let boards ripple and crack at seams years later. The 1.25-per-square-foot convention places fasteners every 8–12 inches on fields and tighter along edges, where movement shows up first.
How it's calculated
The math behind this calculator
Sheets = ⌈ Area ÷ 32 ⌉ Screw weight ≈ Area × 0.004 lb/sq ftEach 4×8 board covers 32 square feet, so total area divided by 32 and rounded up gives the board count. Screws run about 1¼ per square foot; at roughly 320 screws per pound that is approximately 0.004 pounds of screws per square foot of board.
Assumptions & limitations
- 4×8 boards installed vertically with no openings deducted.
- Screw estimate assumes ~1.25 screws per sq ft and ~320 screws per pound.
- Board waste from damage and awkward cuts is absorbed by rounding up; add 5–10% for complex rooms.
Worked example
An 800 sq ft area divides into 25 full boards; and needs about 1,000 screws weighing roughly 3.2 lbs in total.
FAQ
Frequently asked questions
- How many sheets do I need for a 12×12 room?
- Four 8-ft walls give 384 sq ft → 12 sheets of 4×8. Ceilings add 144 sq ft, or about 5 more sheets.
- Should I subtract doors and windows?
- Usually not; offcuts from openings seldom reuse cleanly. Rounding up already provides buffer for typical rooms.
- How many screws per pound?
- Roughly 320 for 1¼" #6 screws. The calculator’s weight estimate uses that assumption alongside ~1.25 screws per sq ft.
- Does this cover mud and tape?
- No. Joint compound and tape scale with seam length, not area; plan roughly 0.05 lbs of compound per sq ft as a rule of thumb.
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