Drywall is cheap per sheet and miserable to run short of — delivery fees on three extra sheets can cost more than the sheets. Enter your room size below for the sheet count, with cuts and waste covered.
How many drywall sheets do you need?
Enter your room size to get the number of drywall sheets to buy — plus a joint compound estimate.
Your estimate
Doors and windows are not subtracted — the waste allowance covers those cut-outs on typical rooms. A 4×8 sheet of 1/2-inch drywall weighs about 50–57 lbs, so plan help (or a panel lift) for ceilings. Use moisture-resistant board in bathrooms and fire-rated board where code requires it (garages, furnace rooms).
How to use this drywall calculator
- Measure the room's length, width and ceiling height.
- Pick the sheet size you plan to buy — 4×8 is standard and easiest to handle.
- Tick 'Include the ceiling' if you are boarding it too.
- Keep the 10% waste allowance; rooms with many corners and openings may need 15%.
How we calculate drywall
Wall area = 2 × (length + width) × ceiling height, plus the ceiling area (length × width) if included. Sheets = area plus waste, divided by the sheet's coverage, rounded up — stores only sell whole sheets. Joint compound is estimated at roughly 1 gallon per 100 sq ft for taping and finishing coats.
Drywall calculator FAQs
How many sheets of drywall do I need for a 12×12 room?
The walls of a 12×12 room with 8 ft ceilings total 384 sq ft — exactly 12 sheets of 4×8 before waste. Buy 14 to cover cuts and mistakes. Adding the ceiling takes the total to 19 sheets.
Should I use 4×8, 4×10 or 4×12 sheets?
Match the sheet length to your ceiling height and wall length to minimize butt seams — the hardest joints to finish invisibly. The 4×8 is easiest to handle and transport; longer sheets mean fewer seams but weigh more and are awkward on stairs and in small rooms.
How much does a sheet of drywall weigh?
A 4×8 sheet of standard 1/2-inch drywall weighs about 50–57 lbs; lightweight panels run closer to 40 lbs. Ceiling work is a two-person job — or rent a panel lift, it is cheaper than a chiropractor.
Do I need special drywall for a bathroom?
Yes — use moisture-resistant board (and cement board inside shower surrounds) anywhere humidity is routine. Standard drywall behind a shower is a mold problem waiting for a date.