Drywall Calculator

Enter the wall dimensions and ceiling height, choose your sheet size, and deduct the openings.

Handles 4×8, 4×10 and 4×12 sheets and gives you the fastener and finishing materials alongside the board count.

How to use the drywall calculator

Why use the Build Tally drywall calculator

Sheet size changes the joint count

Drywall comes in 4 ft widths at 8, 10 and 12 ft lengths. Longer sheets cost more per sheet but produce fewer butt joints, and butt joints are the hardest to finish invisibly because they have no tapered edge. On a 12 ft wall, a single 12 ft sheet run horizontally gives you one tapered joint instead of a butt joint in the middle. If you can get the longer sheets into the room — and that is a real constraint in stairwells and tight hallways — they usually give a better finish.

What to deduct and what not to

Deduct large openings such as doorways and picture windows, because you genuinely do not board over them. Do not deduct small windows or every doorway on a plan-by-plan basis, since the offcuts around openings are rarely large enough to use elsewhere. This calculator takes your opening area off the total and then rounds sheets up, which lands close to what you will actually buy. Add a sheet or two if the room has many small walls and returns.

Screws, tape and compound

Figure roughly one pound of screws per 1,000 square feet for walls at standard spacing, more for ceilings where fasteners are closer. Joint tape runs about 380 linear feet per standard roll and you need enough for every seam plus the internal corners. All-purpose compound covers around 100–140 square feet of board per gallon across taping and two finish coats, so a small room typically takes one bucket. Setting-type compound for the first coat gives a harder joint and dries faster.

Read the guide: How Much Paint Do I Need? Gallons Per Room, Worked Out