Drywall Calculator

Estimate board quantity from wall area

Enter one rectangular wall's length and height, total opening area, extra allowance, and board dimensions. The result divides adjusted wall area by board area and rounds up to whole boards.

How the estimate works

Wall length multiplied by height gives gross square footage. Entered door and window area is subtracted to find net area. The allowance percentage increases that net amount for planning, then the adjusted area is divided by one board's width times length. Because a fraction of a board is generally purchased as a whole board, the count rounds upward.

Worked example

A 16-foot wall that is 8 feet tall has 128 square feet. Subtracting a 20-square-foot opening leaves 108 square feet. A 10% allowance raises the planning area to 118.8 square feet. Each 4-by-8 board covers 32 square feet by area, so 3.7125 boards becomes an estimate of 4 whole boards.

Area does not produce a cut layout

Two walls with the same area can need different board counts after seams, orientation, staggered joints, edge support, and cut reuse are considered. This calculator does not place boards on a wall or prove that the displayed count can be cut into a workable layout. Sketch actual board placement before purchasing, especially around many openings or short wall sections.

Measure the intended surface

Calculate separate walls and ceilings separately, then add their board counts only after checking board size and layout for each surface. Enter the combined area of openings only when you intend to subtract them. Small openings sometimes create little usable savings because surrounding cuts still consume most of a board.

Assumptions and limitations

This is quantity arithmetic, not construction, structural, fire-safety, moisture-control, acoustic, code, or installation advice. It does not select thickness or board type, check framing, count screws, tape, compound, corner bead, adhesive, lifts, labor, or delivery. The allowance is editable and is not a recommendation. Confirm materials and methods for the actual project with applicable instructions and requirements.