Drywall Calculator & Room Planner

Take the wall area, subtract door and window openings, add the ceiling if you are covering it, add ten percent for waste, and divide by the sheet area — 32 sq ft for a 4 × 8 sheet. This planner does exactly that with your room's numbers.

Longer sheets mean fewer butt joints, which are the hardest joints to finish invisibly. They are also heavy and awkward to get into a room. For DIY work in an average bedroom, 4 × 8 is usually the practical choice.

Around five pounds per sheet across three coats is a common planning allowance, which is roughly one 4.5-gallon bucket per twelve sheets. Actual usage varies a lot with technique — buy one bucket and judge from there.