Drywall Layout Calculator

How the layout planner places sheets

1. The ceiling goes up first, so its offcuts are available for the walls, the same order you would hang the room.
2. Walls are hung in horizontal rows starting at the ceiling line. Any strip lands at the floor, where baseboard covers the cut edge.
3. An opening that spans a whole row, like a garage door through the bottom rows, leaves a gap in that row. Smaller openings are boarded over and cut out, which is how they are actually hung.
4. Before cutting a new sheet, the planner looks for an offcut that is thick enough for the row and either finishes the run or is at least 4 ft long. Shorter stubs add a butt joint for almost no board, so they are left as scrap.
5. Ripped strips are kept: a 1 ft strip for a 9 ft wall leaves a 3 ft by 12 ft piece that covers the next three walls.

Auto mode runs the room both ways, horizontal and vertical, for walls and ceiling, and keeps the plan with the fewest sheets. When two plans tie on sheets, it keeps the one with fewer butt joints, since those are the hardest seams to finish flat.

Reading the diagrams

Each wall is drawn to scale as you would see it from the middle of the room, floor at the bottom. Every piece of board is a rectangle with the number of the sheet it came from. Plain pieces are cut from a new sheet; shaded pieces are offcuts reused from an earlier one, so you can see exactly which leftover goes where.

Openings are drawn dashed with a cross. If a piece runs over an opening, that is deliberate: hang the full piece, then cut the opening out with a router or saw. The butt joint count under each wall is the number of end-to-end joints in that wall, which is the best quick measure of how much finishing work the layout creates.

How the planner and the main calculator agree

The main drywall calculator runs this same layout engine. It puts doors near the corners and windows centered on the walls, boards over any custom openings, and adds the waste allowance as spare sheets. With the default 10% its count matches the planner's buy number for the same room.

The planner lets you put each opening where it really is and see every cut. That matters most on tall walls. A 12 by 12 room with 9 ft walls in 4x12 board lays out in 9 sheets, because one sheet ripped into four 1 ft strips covers the bottom of all four walls; a plain area estimate with 10% waste says 10. The planner adds one spare per ten sheets for breakage and miscuts, so you buy 10 either way, and you know where each piece goes.

A plan is only as good as the cutting. If you are new to ripping long strips, or the board will be carried up stairs where corners get broken, buy a couple of spares beyond the plan.

Layout rules worth following on any job

• Run walls horizontally in homes. It puts the tapered seam at a comfortable working height and bridges studs that are not quite in plane.
• Use the longest sheet you can carry into the room. Each extra sheet in a row is another butt joint to feather out.
• Stagger butt joints between rows so they never line up on the same stud.
• Do not break a joint at the corner of a door or window. Run the sheet past the opening and cut it out, which avoids the cracks that start at those corners.
• Hang the ceiling before the walls, so the wall board holds up the ceiling edges.