Property Repair Calculators

Drywall Calculator

A 4 × 8 sheet of drywall covers 32 sq ft. Add up your walls and ceilings, subtract doors and windows, add a waste allowance, and divide by the sheet size to get how many sheets to buy. This calculator also estimates joint compound, tape, and screws from manufacturer coverage figures. [1]

Results

4 × 8 ft sheets to buy

551 sq ft of board + 10% waste

Net wall area: 383 sq ft
Ceiling area: 168 sq ft
Board area: 551 sq ft
Sheets (4 × 8 ft): 18.94 → 19
Joint compound (4.5 gal pails): 2
Joint tape (250 ft rolls): 1
Drywall screws: 760

Longer sheets mean fewer butt joints to tape, but they are heavier and harder to carry up stairs. Finishing quantities are based on the board you hang, so they include the waste allowance.

How this was calculated

Walls 416 − openings 33 = 383 sq ft
+ ceilings 168 = 551 sq ft of board
With 10% waste = 606.1 sq ft
Sheets = 606.1 ÷ 32 sq ft (4 × 8 ft) = 18.94 → 19
Board hung = 19 × 32 = 608 sq ft
Compound = 608 ÷ 1,000 × 10 gal = 6.08 gal → 2 × 4.5 gal
Tape = 608 ÷ 1,000 × 370 ft = 225 ft → 1 × 250 ft rolls
Screws = 608 ÷ 1,000 × 1,250 → 760

Worked example

A 12 × 14 ft room with 8 ft walls and the ceiling, one 3 × 7 ft door and one 3 × 4 ft window, 4 × 8 sheets, and 10% waste.

Walls:    416 − 33 openings = 383 sq ft
Ceiling:  12 × 14 = 168 sq ft
Board:    551 sq ft × 1.10 = 606.1 sq ft
Sheets:   606.1 ÷ 32 = 18.94 → 19 sheets
Compound: 608 sq ft hung ÷ 1,000 × 10 gal = 6.08 gal → 2 × 4.5 gal pails
Tape:     608 ÷ 1,000 × 370 ft = 225 ft → 1 × 250 ft roll
Screws:   608 ÷ 1,000 × 1,250 → 760

How the formula works

board area = walls − doors and windows + ceilings
sheets     = board area × (1 + waste %) ÷ sheet size, rounded up
compound   = sheets × sheet size ÷ 1,000 × gal per 1,000 sq ft, rounded up to whole pails
tape       = sheets × sheet size ÷ 1,000 × ft per 1,000 sq ft, rounded up to whole rolls
screws     = sheets × sheet size ÷ 1,000 × screws per 1,000 sq ft, rounded up

Sheets round up once, after waste. Finishing materials are based on the board you actually hang (whole sheets), because offcuts that end up on the wall still get taped, mudded, and screwed.

Limitations

Waste depends on the room. Many openings, short walls, and soffits waste more; long plain walls waste less. The 10% default is an editable assumption, not a manufacturer figure.
Coverage figures are manufacturer averages for a standard finish. Higher finish levels, textured walls, and extra skim coats use more compound.
Screws per 1,000 sq ft come from a Georgia-Pacific estimating table for 1/2 in and 5/8 in board. Actual spacing depends on framing, local code, and whether adhesive is used.
Corner bead, primer, and texture are not included.
Water-damaged drywall should be removed to at least the wet line; check for moisture and mold before replacing it.

Common scenarios

Flood cut after a water loss: enter each wall with the height of the cut (for example 2 or 4 ft) instead of the full wall height, and turn off the ceiling.
Ceiling only (a leak stain): remove the walls, keep the ceiling, and set waste higher if the patch area is irregular.
9 ft walls: try 4 × 10 or 4 × 12 sheets hung horizontally. Longer sheets can reduce the number of butt joints.
Checking a contractor’s estimate: enter the square footage on their estimate as a single wall with a height of 1 ft, and set waste to 0% if their figure already includes it.

Common questions

How many sheets of drywall do I need for a 12 × 12 room?

With 8 ft walls, the four walls are 384 sq ft and the ceiling is 144 sq ft. Before openings and waste that is 528 sq ft, or 16.5 sheets of 4 × 8. Subtract doors and windows and add waste in the calculator for your room.

How much joint compound do I need?

USG lists about 10 gallons of Sheetrock All Purpose Joint Compound per 1,000 sq ft of board. A 4.5-gallon pail covers roughly 450 sq ft at that rate.

How much drywall tape per sheet?

USG lists about 370 ft of paper tape per 1,000 sq ft of board, or about 12 ft per 4 × 8 sheet. A 250 ft roll covers roughly 675 sq ft.

How many screws per sheet of drywall?

Georgia-Pacific’s estimating table lists about 1,250 screws per 1,000 sq ft, which works out to about 40 per 4 × 8 sheet. Spacing depends on the framing and code.

Should I subtract doors and windows?

Yes for an accurate count. Small openings are often cut out of whole sheets, so some installers subtract only large openings and let the rest cover waste.

Sources and methodology

Finishing defaults are manufacturer figures for specific products, used as editable starting points. The waste percentage is an editable assumption; no manufacturer figure was found. This page is quantity only: it uses no prices.

[1] USG — Sheetrock All Purpose Joint Compound submittal sheet (J1969). Retrieved 2026-09-25. USG Sheetrock All Purpose (ready-mixed): “Coverage: Approximately 10 gal./1,000 sq. ft. … of gypsum panels.” Packaging: 4.5 gal pail, 3.5 gal carton, and 4.5 gal carton.
[2] USG — Sheetrock Paper Joint Tape submittal sheet (J1736). Retrieved 2026-09-25. USG Sheetrock Paper Joint Tape: “Coverage: Approx. 370 ft. per 1,000 sq. ft. … gypsum panels.” Georgia-Pacific gives 350 lineal feet per 1,000 sq ft as typical usage. USG lists 75, 250, and 500 ft rolls; 250 ft is described as the “popular size for hand-application joint treatment.”
[3] Georgia-Pacific — ToughRock Gypsum Board Wallworks Guide. Retrieved 2026-09-25. Georgia-Pacific’s “Estimating Gypsum Board Fasteners” table: approx. 1,250 screws per 1,000 sq ft for 1/2 in and 5/8 in board (1-1/8 in and 1-1/4 in screws). The same guide spaces ceiling screws at 12 in.

This tool provides an educational estimate only. Insurance companies, contractors, and building officials may calculate these figures differently depending on policy language, property condition, local pricing, and applicable codes.

Disclaimer: Calculators and information on this site are provided for educational and estimating purposes only. Results do not determine insurance coverage, claim payments, repair requirements, or professional recommendations.