Drywall Calculator
Sheets, joint compound, screws, and tape for a room.
Longer sheets mean fewer joints but are heavy. 4x8 is the DIY standard.
You need
17 sheets
Waste included. Screws assume framing at 16 in on center.
- Surface area
- 477 sq ft
- Joint compound (4.5 gal)
- 2 buckets
- Drywall screws
- 475 screws
- Joint tape (500 ft rolls)
- 1 rolls
Estimates only. Verify quantities before ordering.
How this is calculated
Area = 2 x (length + width) x height, minus 21 sq ft per door and 15 sq ft per window, plus length x width if the ceiling is included. Sheets = area x (1 + waste) / sheet area, rounded up. Compound assumes one 4.5 gallon bucket per 450 sq ft, screws about one per square foot, tape about 37 ft per 100 sq ft.
This calculator takes a room's dimensions, subtracts standard allowances for doors and windows, optionally adds the ceiling, and converts the total into sheet counts for your chosen panel size. It also estimates the finishing materials people forget to buy: joint compound, screws, and tape.
Waste matters more with drywall than with most materials because offcuts around openings, outlets, and odd corners are rarely reusable. 10% is a good default for simple rectangular rooms. Bump it to 15% for rooms with many openings, angled walls, or ceilings that need cutting around fixtures.
Drywall sheets for common rooms
Rows cover walls and ceiling with 8 ft walls, one door, two windows, 4 x 8 sheets, and 10% waste.
| Room size | 4 x 8 sheets | Surface area |
|---|---|---|
| 10 x 10 ft | 13 sheets | 369 sq ft |
| 12 x 10 ft (bedroom) | 15 sheets | 421 sq ft |
| 12 x 12 ft | 17 sheets | 477 sq ft |
| 15 x 12 ft (living room) | 20 sheets | 561 sq ft |
| 24 x 24 ft (2-car garage) | 45 sheets | 1,293 sq ft |
Board types and where each is required
Standard white board suits most walls and ceilings. Moisture-resistant board, traditionally green, is for damp rooms such as bathrooms and laundries, though it is not waterproof and does not belong in a shower enclosure, where cement board or a purpose-made tile backer is required. Paperless glass-mat boards resist mold better still and are worth the premium in bathrooms.
Type X is fire-rated board, made thicker at 5/8 inch with glass fibers in the core, and it is required by code in specific assemblies: the wall and ceiling between an attached garage and living space, and in many multi-family separations. This is not an optional upgrade, and inspectors check it, so confirm the requirement before ordering for a garage.
Specialty boards cover the remaining cases. Sound-dampening panels use a viscoelastic layer to reduce transmission between rooms, flexible board bends around curved walls, and abuse-resistant board suits hallways and garages. Each costs more and is worth it in narrow circumstances rather than throughout a project.
Thickness and orientation
Half inch board is standard for walls. Ceilings are the case where thickness matters most: half inch board sags between joists spaced 24 inches apart, particularly under blown insulation, so use 5/8 inch on ceilings or specify sag-resistant half inch board rated for that spacing. A quarter inch board exists for laminating over existing surfaces and has no structural use on its own.
On walls, hanging sheets horizontally is standard practice for good reasons: it puts the tapered seam at a comfortable working height, it produces fewer linear feet of joint than vertical hanging on an 8 foot wall, and it ties more studs together. Vertical hanging makes sense on tall walls and where a factory edge can land neatly on a corner.
Stagger the joints between rows and between the two sides of a wall so that seams do not stack. Butt joints, where two cut ends meet without a tapered edge, are the hardest to hide and should be minimized and placed away from windows and other raking light.
Finish levels, and choosing one
The industry defines finish levels 0 through 5, and knowing them saves arguments. Level 3 is a taped and coated surface suitable for heavy texture. Level 4 is the residential standard: joints and fasteners coated and sanded smooth, appropriate for flat paint and light texture. Level 5 adds a skim coat over the entire surface.
Level 5 is worth it in specific conditions: large walls in raking light from a window or a row of downlights, and any wall getting a gloss or semi-gloss finish. Under those conditions the difference in surface porosity between the joint compound and the paper face shows through as visible banding, called joint photographing, and no amount of extra paint hides it.
For most rooms, level 4 with a quality primer is genuinely sufficient, and a high-build or drywall-specific primer closes much of the gap for a fraction of the labor of skimming an entire room. Deciding which level you are aiming for before starting determines how much compound to buy and how many coats to plan.
Common questions
What size drywall sheet should I use?
4x8 sheets are the DIY default: light enough to handle and they fit in a pickup. 4x12 sheets produce fewer joints to tape, which is why pros prefer them, but a 12 foot sheet of 1/2 inch drywall weighs over 80 lb and really needs two people or a lift.
How many screws per sheet of drywall?
With studs at 16 inches on center, a 4x8 sheet takes roughly 32 screws: one every 12 inches in the field and every 8 inches on edges is a common pattern, and ceilings get screws slightly closer together. That works out to about one screw per square foot, which is what this calculator uses.
How much joint compound does a room take?
Plan on about one 4.5 gallon bucket of all-purpose compound per 450 to 500 square feet of drywall for a standard three-coat finish. Textured finishes and skim coats use significantly more, so buy an extra bucket if you are texturing.
Do you hang the ceiling or the walls first?
Ceiling first, always. The wall sheets then push up against the ceiling sheets and support their edges, which reduces cracking at the corner joint. Rent a drywall lift for ceilings; it is inexpensive and saves your back and the sheets.