Openings and ceilings
This estimate does not deduct windows or doors and does not include the ceiling. That is often acceptable for rough planning, but use a measured sheet layout.
Example
A 14 ft by 12 ft room with 8 ft walls has wall area of 2 x (14 + 12) x 8 = 416 square feet. With 10% waste, that becomes about 458 square feet before dividing by sheet area.
Common mistakes
Check whether you want to include ceilings, closets and waste from cutouts. Sheet orientation can also change the number of sheets needed.
Limitations
This calculator estimates sheet count only. It does not include joint compound, tape, screws, corner bead, fire-rated assemblies or local code requirements.
Last reviewed: 2026-05-17