Drywall Calculator

Calculate drywall sheets, tape, mud, and screws needed for a room. Includes waste factor.

By Konstantin Iakovlev · Updated September 2026 · Source: HomeAdvisor

ft
ft
Sheet Size

Total Wall Area

327 sqft

incl. 10% waste

Sheets Needed

11

Estimated Cost

$179.00

Materials Breakdown

Gross Wall Area384 sqft
Door Deductions87 sqft
Net Wall Area297 sqft
With 10% Waste327 sqft
Drywall Sheets11 sheets
Joint Tape132 ft
Joint Compound (Mud)4.0 gallons
Screws308

Cost Estimate

Drywall Sheets$132.00
Tape$8.00
Joint Compound$15.00
Screws$24.00
Total Materials Cost$179.00

Use the Drywall Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only. Results are estimates from the numbers you enter and the assumptions described on this page; check them against local building codes, product specifications and current prices, and have structural, electrical or gas work designed or checked by a licensed professional.

How It Works

Pinning down how many drywall sheets, how much joint compound, and how many fasteners a job needs is what separates a smooth build from one stalled by repeat trips to the supplier. A tight estimate keeps both overspending and schedule slips in check.

The calculator totals wall area only, as wall length × height × the number of walls, so walls of different lengths need an average length and a ceiling has to be figured as a separate run. It takes out 21 sq ft per door and 15 sq ft per window, adds a 10% waste allowance and divides by the sheet size (32 sq ft for a 4x8, 40 for a 4x10, 48 for a 4x12), rounding up. Screws are counted at 28 per sheet and tape at half of each sheet's perimeter, and joint compound is estimated from the same area.

Round sheet counts up rather than down, because trimming partial sheets only generates scrap, and pad the order further when the layout throws in lots of corners or angles. Factor in changes in ceiling height as well.

Example: Four Walls of a 12 × 12 ft Room

  1. 1 Input: wall length 12 ft, wall height 8 ft, 4 walls, 4' x 8' sheets, 2 doors and 3 windows (the calculator's defaults).
  2. 2 Gross wall area: 12 × 8 × 4 = 384 sq ft. Openings: 2 × 21 + 3 × 15 = 87 sq ft. Net: 297 sq ft.
  3. 3 With 10% waste: 297 × 1.10 = 326.7 sq ft, and 326.7 ÷ 32 = 10.2, rounded up to 11 sheets, or $132 at the default $12 per sheet.
  4. 4 Tape: 11 sheets × 24 ft perimeter × 0.5 = 132 ft. Screws: 11 × 28 = 308. For the 12 × 12 ceiling, run it again as one 12 × 12 ft wall with no doors or windows: 144 × 1.10 ÷ 32 = 4.95, so 5 more sheets.

Source: HomeAdvisor · Last updated: September 2026

Frequently Asked Questions

How many sheets of drywall do I need for a room?
Calculate wall and ceiling area in square feet, then divide by 32 (for 4x8 sheets) or 48 (for 4x12 sheets). Add 10-15% for waste and cuts. A 12x12 room with 8-foot ceilings needs about 18-20 sheets for walls and ceiling.
How much does it cost to drywall a room?
This calculator totals materials only: sheets at the price you enter ($12 each by default) plus tape, joint compound and screws. Hanging, taping and finishing labor is not included and varies by region and finish level, so get quotes from local drywall contractors.
What thickness of drywall should I use?
Use 1/2-inch for most walls and ceilings with standard 16-inch on-center framing. Use 5/8-inch for fire-rated walls, ceilings below living spaces, and to reduce sagging on 24-inch on-center framing. Use 1/4-inch for curved surfaces.

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