Drywall Calculator

Wall area is length × height × number of walls. Subtract a flat allowance for doors and windows to get the net coverage area. Divide by the sheet area for your chosen size (32 sq ft for 4×8, 40 for 4×10, 48 for 4×12). Multiply by one plus the waste percent and round up to the next whole sheet.

4 × 8 ft sheets are the easiest to maneuver in a residential job and the standard for DIY work. 4 × 10 and 4 × 12 sheets reduce the number of horizontal joints on long walls (and the amount of taping you have to do), but they're heavier and need at least two people to handle. Pick the largest size you can move into the room.

10 percent covers most residential rooms with average cuts. Increase to 12 to 15 percent for rooms with many windows or doors, lots of inside corners, sloped ceilings, or oddly shaped spaces. The waste percent is added on top of the bare sheet count before rounding up.

Not by default. Add the ceiling as an extra row by treating it as a single wall: length × width with one wall count, no doors or windows. Add the resulting sheet count to your wall total. Ceiling drywall is often heavier and the 5/8 inch product is common for fire ratings; check local code before ordering.

Those are not included in the sheet count. A rule of thumb for the rest of the order is one box of drywall screws, one roll of joint tape, and one bucket of pre-mixed joint compound per 400 to 500 square feet of drywall, plus corner bead for any outside corners. Quantities vary by finisher and product.

Yes for full-height openings. The calculator subtracts 20 sq ft per door and 15 sq ft per window as a planning default. For larger openings (sliding doors, picture windows, archways) deduct the actual square footage manually by subtracting them from the wall area you enter as length × height × walls.