Interior

Drywall Calculator: Sheets, Screws, Mud and Tape

Sheet count for walls and ceiling, plus the screws, joint compound and tape that always get forgotten on the first trip.

Your measurements

Drywall to buy

20sheets

4 × 8 ft sheets covering 554 sq ft plus 10% cutting waste

Wall area
416 sq ft
Ceiling area
168 sq ft
Less openingsCredited at half value
−30 sq ft
Board area
554 sq ft
Screws~720 screws at 36 per sheet
3 lb
Joint compoundAll-purpose, covers ~475 sq ft per bucket
2 × 4.5 gal buckets
Joint tapePaper tape; buy the next whole roll up
582 ft
Corner beadRough allowance — count your actual outside corners
32 ft
  • Hang the ceiling first, then the walls — the wall sheets hold up the ceiling edge and give you a tighter joint.
  • Longer sheets mean fewer butt joints, and butt joints are the hardest thing to finish invisibly. If you can get 12 ft sheets into the room, use them.
  • Order 5/8 in board for ceilings and any garage-to-house wall. 1/2 in sags on 24 in ceiling framing and fails fire code in attached garages.

How this is calculated

  • Board area is wall area plus ceiling, less half the area of doors and windows — half rather than full, because a sheet cut around an opening seldom yields a usable second piece.
  • A 10% cutting allowance is added before dividing by sheet area and rounding up.
  • Screws are estimated at 36 per sheet (a 16 in on-centre field pattern) at roughly 300 screws per pound.
  • Joint compound assumes a 4.5 gallon bucket of all-purpose covers about 475 sq ft of board across tape, fill and finish coats. Tape is 1.05 linear feet per square foot of board.

Quantities are rounded up, because materials are sold in whole units and a second trip costs more than a spare box. Cost figures are typical US ranges and are not a quote — always price against your own supplier.

Frequently asked questions

How many sheets of drywall do I need for a 12x12 room?

With 8 ft ceilings that is 384 sq ft of wall plus 144 sq ft of ceiling. After opening credits and a 10% waste allowance you need about 18 sheets of 4×8, or 12 sheets of 4×12.

How much joint compound do I need?

About one 4.5 gallon bucket per 475 sq ft of board for a standard three-coat finish. A level 5 finish, or a first-time DIY job with heavy sanding, can use 50% more.

Should I use 1/2 inch or 5/8 inch drywall?

1/2 in is standard for walls. Use 5/8 in on ceilings — especially over 24 in on-centre framing, where 1/2 in will sag — and on any wall between an attached garage and living space, where it is a fire-rating requirement.

Know the quantities. Now see the room.

You have the numbers for the job. Upload a photo of the room and see what it looks like finished, in any style, before you buy a single box.

Try the AI room designer

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