Drywall Calculator

Get an accurate drywall takeoff in seconds. Enter your room dimensions, doors, windows, and ceiling option to see total square footage, 4x8 sheet count, screws, joint compound buckets, and tape rolls with a built-in 10% waste factor.

How This Calculator Works

The calculator builds total board area from the room's geometry. Wall area is the perimeter times height — 2 × (length + width) × height. From that it subtracts openings: about 21 sq ft per door (a 3×7 opening) and 15 sq ft per window. If you are rocking the ceiling too, it adds length × width on top. That paintable board area is then padded by 10% for waste, because every cut, butt joint, and bad corner wastes material.

Sheets are the padded area divided by 32 square feet — the area of one 4×8 panel — rounded up. Fasteners and finishing scale with area: roughly one pound of screws (about 320 screws) per 500 sq ft, and one container of joint compound plus one roll of tape per 500 sq ft. Those ratios match how I order for production hanging, where you grab a tub of mud and a roll of tape for every couple of rooms.

A Worked Example

A 12×14 ft bedroom with 8 ft ceilings, two doors, and two windows, ceiling included. Wall area: 2 × (12 + 14) × 8 = 416 sq ft. Subtract openings: 2 doors × 21 + 2 windows × 15 = 72 sq ft, leaving 344. Add the ceiling, 12 × 14 = 168, for 512 sq ft. Pad 10% to 563 sq ft. Divide by 32 and round up: 18 sheets of 4×8. That also calls for about 1 lb of screws, one tub of mud, and one roll of tape.

Estimator's tip: Hang the longest sheets your access allows and run them horizontally on standard 8-foot walls — one seam at 4 feet beats a row of vertical butt joints to tape. I keep my sheet count from the calculator but always grab two or three extra sheets on a big job; a cracked corner or a re-measured closet costs far less as spare stock than as a second trip to the supply house.

What Affects Your Sheet Count

• Ceiling inclusion — rocking the lid can add a third or more to your sheet count.
• Sheet size: this tool figures 4×8 panels; 4×12 sheets cover the same area in fewer pieces with fewer butt joints.
• Number and size of openings you deduct for doors and windows.
• Ceiling height — 9 or 10 ft walls push you into taller sheets or more horizontal seams.
• Waste from cuts, closets, and odd angles; the built-in 10% covers a typical room.
• Whether you need moisture- or fire-rated board, which changes price but not the count.

Frequently Asked Questions

How many drywall sheets do I need for a room?

Find total wall and ceiling area, subtract doors and windows, add 10% waste, then divide by 32 for 4x8 sheets. A standard 12x12 room with 8 ft ceilings usually takes 12 to 16 sheets.

How much joint compound and tape per sheet?

Roughly one tub of all-purpose compound and one 500-foot roll of tape per 500 square feet of board, which is about every 15 to 16 sheets. The calculator scales both with your area.

Should I use 4x8 or 4x12 drywall?

4x8 sheets are easier to carry and fit most DIY jobs; 4x12 sheets reduce the number of butt joints on long walls, giving a flatter finish, but they are heavy and awkward in tight spaces.

How many screws per drywall sheet?

About 32 screws per 4x8 sheet using standard 12-inch field spacing on walls. That works out to roughly one pound of screws for every 500 square feet of board.