How much joint compound and tape do I need?

Allow about one gallon of premixed joint compound per 100 square feet of drywall for taping and three finish coats, and about 40 feet of tape per 4 by 8 sheet. A 4.5 gallon box of compound covers roughly 450 to 475 square feet.

How many screws per sheet of drywall?

About 32 screws for a 4 by 8 sheet on walls with studs 16 inches apart, placed every 12 inches in the field and 8 inches along the edges. Ceilings need more, around 36 to 40 per sheet.

Should I subtract doors and windows?

Usually no. You still cut the sheet and the offcut is rarely reusable, so most estimators leave openings in and let the waste allowance cover them. For a very large opening like a garage door, subtract it.

Home / Drywall Calculator

Drywall Calculator

A drywall calculator tells you how many sheets a room needs, plus the screws, joint compound, and tape to finish it, and the cost. It takes the room size, whether you are boarding the ceiling, and the sheet size. Type your room below. Everything runs in your browser, with no signup.

Updated for 2026

Your room

Enter the dimensions and pick the sheet size. Results update instantly.

Length

Width

Wall height

Boarding the ceiling?

Sheet size

Price per sheet

$/ sheet

Drywall to buy

Area to board

0 ft²

Screws

Joint compound

0 gal

Tape

0 ft

Sheet cost

Drywall sheets for common rooms

Sheets of 4 by 8 drywall for the walls of a room with 8 foot ceilings, with 10% waste. Tap any row to load it.

Room	Size	Wall area	Sheets (4x8)

How the drywall estimate is calculated

The area to board is the room perimeter times the wall height, plus the ceiling if you board it. Add a waste allowance, then divide by the sheet size:

Sheets = ( Perimeter × Height + Ceiling ) × (1 + Waste) ÷ Sheet area

A 4 by 8 sheet is 32 square feet and a 4 by 12 is 48. Openings are normally left in, since the offcut is rarely reusable and the 10% waste covers them. For supplies, allow about 32 screws per sheet, one gallon of premixed joint compound per 100 square feet for taping and three coats, and about 40 feet of tape per sheet.

Worked example (Stand: 2026)

Room12 ft × 14 ft, 8 ft walls
Perimeter (2 × (12 + 14))52 ft
Wall area (52 × 8)416 ft²
With 10% waste458 ft²
Sheets (458 ÷ 32)15 sheets
Screws (15 × 32)480
Joint compound (416 ÷ 100)5 gal
Sheet cost (15 × $15)$225

Frequently asked questions

How many sheets of drywall do I need?

Multiply the perimeter by the wall height for the area, add 10 percent waste, then divide by the sheet size (32 square feet for 4 by 8). The calculator above does this and also gives screws, compound, and tape.

How much joint compound and tape?

About one gallon of premixed compound per 100 square feet of board, and roughly 40 feet of tape per 4 by 8 sheet. A 4.5 gallon box covers about 450 to 475 square feet.

How many screws per sheet?

About 32 for a 4 by 8 wall sheet on studs 16 inches apart. Ceilings take a few more, around 36 to 40 per sheet.

Do I subtract doors and windows?

Usually no. The offcut is rarely reusable, so the waste allowance covers normal openings. Subtract only very large openings like a garage door.

Does this calculator store my numbers?

No. Everything is calculated in your browser. Nothing you enter is sent to a server or saved.

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