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Drywall Calculator

Calculate drywall sheets, joint compound, tape, and screws for a room. Subtracts doors and windows automatically.

Construction

Drywall Calculator

Generated on April 25, 2026

Materials
Sheets needed (4×8)21
Total drywall area595 ft² (595 ft²)
Wall area403 ft²
Ceiling area192 ft²
Joint compound2 buckets
Joint tape595 ft
Drywall screws~672

Room layout (top-down)

L = 16 ftW = 12 ft1 door · 2 windows

Step-by-step calculation

Formula

Wall area = perimeter × height − openings. Ceiling area = L × W (if included). Sheets = ceil(area ÷ sheet area × (1 + waste%)).

  1. 1Room: 16 × 12 × 8 ft (perimeter = 56 ft).
  2. 2Wall area (with openings deducted): 56 × 8 − 45.0 = 403.0 ft².
  3. 3Ceiling area: 16 × 12 = 192.0 ft².
  4. 4Total area: 595.0 ft² = 595 sq ft.
  5. 5595 ÷ 32 sq ft per sheet × 1.10 (10% waste) = 21 sheets.
  6. 6Joint compound: ~1 bucket per 450 sq ft → 2 buckets.
  7. 7Joint tape: ~1 ft per sq ft → 595 ft.
  8. 8Drywall screws: ~32 per sheet → 672 screws total.

?What is the Drywall Calculator?

The Drywall Calculator estimates how many drywall sheets (4×8, 4×10, or 4×12 ft), buckets of joint compound, feet of joint tape, and drywall screws you need to finish a room. Subtracts doors (~21 sq ft each) and windows (~12 sq ft each) automatically — so you don't over-order. Optionally includes the ceiling, which adds floor area to the total. Used by drywall contractors, DIY home renovators, and anyone planning a room addition or basement finish.

The Formula

Wall area = perimeter × ceiling height − openings. Ceiling area = length × width. Sheets = ceil(area ÷ sheet_area × (1 + waste%)).

A standard 4×8 sheet covers 32 sq ft; 4×12 covers 48 sq ft (preferred for fewer butt joints in tall ceilings). Joint compound usage averages ~1 bucket (50 lb) per 450 sq ft of drywall (for 3 coats: tape, fill, finish). Joint tape is ~1 ft per sq ft of drywall as a rough rule (covers all the seams). Drywall screws: ~32 per 4×8 sheet at 16-inch framing centers (8 along each long edge, 16 in the field).

Practical Examples

1

16×12 ft room with 8 ft ceilings, 1 door + 2 windows: walls = (16+12)×2×8 = 448 sq ft − 21 (door) − 24 (2 windows) = 403 sq ft. With 10% waste = 13.8 → 14 sheets of 4×8.

2

Add the ceiling (16×12 = 192 sq ft) → 595 sq ft total → 21 sheets.

3

Joint compound: 595 ÷ 450 = 1.3 → order 2 buckets minimum.

4

Drywall screws: 21 sheets × 32 ≈ 670 screws. Buy a 1 lb box (~250 screws) — get 3 boxes.

5

Larger sheet sizes (4×10, 4×12) reduce the number of butt joints (the hardest seams to hide) but are heavier and harder to maneuver in tight spaces.

Frequently Asked Questions

Drywall doesn't go over doors and windows — they have casings/jambs. Standard interior door = 21 sq ft (3'×7'); standard window = 12 sq ft (3'×4'). Subtracting prevents over-ordering.

Popular Conversions

Jump to a ready-made conversion — useful for quick reference and sharing:

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