Drywall Calculator
Calculate how much drywall you need — enter your room size and sheet size to get the number of sheets plus joint compound, tape and screws, with a waste allowance.
How many sheets of drywall do I need?
Add up the area you’re covering — the wall area (perimeter × ceiling height) plus the ceiling if you’re hanging it — add a waste allowance, then divide by the area of one sheet. The calculator above does this and also estimates joint compound, tape and screws to finish the job.
sheets = (wall area + ceiling) × (1 + waste%) ÷ sheet area
How thick is drywall?
| Thickness | Where it’s used |
|---|---|
| 1/2 inch | Standard for most walls |
| 5/8 inch (Type X) | Ceilings, garages, fire-rated walls |
| 3/8 inch | Over existing surfaces, repairs |
| 1/4 inch | Curved walls, double-layer |
Sheets are most often 4×8 ft (32 sq ft); 4×12 ft cuts down on seams on big walls. For the rest of the room, see the paint, tile and flooring calculators.
Frequently asked questions
How many sheets of drywall do I need?
Add up the wall area (the room perimeter times the ceiling height) plus the ceiling if you are covering it, then divide by the area of one sheet — 32 square feet for a 4×8 sheet or 48 for a 4×12 — and add a waste allowance. The calculator above does this and also estimates mud, tape and screws.
How thick is drywall?
Standard wall drywall is 1/2 inch thick. Ceilings and garages or other fire-rated areas often use 5/8 inch (Type X) for extra sag resistance and fire protection, while 1/4 and 3/8 inch sheets are used for curved walls and for going over existing surfaces. Half-inch is the right default for most walls.
How much joint compound do I need?
As a rough guide, plan on about 1 gallon of ready-mix joint compound for every 100–150 square feet of drywall across taping and two or three finish coats. The calculator estimates the gallons from your total area; textured finishes use more.
What size sheets does drywall come in?
The most common sheet is 4×8 feet (32 sq ft); 4×12 (48 sq ft) is used on larger walls and ceilings to cut down on seams, and 4×9 and 4×10 are also available. Bigger sheets mean less taping but are heavier to handle. Pick your sheet size above.