Number Drywall Calculator
Drywall is bought by the sheet and hung by the wall — the conversion is where projects under-buy. Enter the room, choose whether the ceiling is in, and get sheets for both panel sizes, a screw estimate, and the material cost.
Openings (doors, windows) are not subtracted — pros order the sheet count whole and cut around them; the offcuts cover mistakes and closets. Screw estimate: about 32 per sheet into studs and joists at standard spacing.
How it works
Wall area = perimeter × ceiling height — (length + width) × 2 × height. The ceiling, if included, adds length × width. Sheets = total area ÷ sheet size (32 sq ft for 4×8, 48 for 4×12), rounded up, because partial sheets still ship as sheets. Screws are estimated at 32 per sheet, the field standard for walls and ceilings at 16-inch spacing.
Formula & worked example
Formula: Wall area = 2 × (length + width) × ceiling height; add length × width when the ceiling is included. Sheets = total area ÷ sheet area (32 sq ft for 4×8, 48 sq ft for 4×12), rounded up. Screws ≈ 32 per sheet at standard spacing.
Worked example: A 12 × 10 ft room with 8 ft ceilings: walls are 352 sq ft and the ceiling 120, totalling 472 sq ft — 15 sheets of 4×8 or 10 sheets of 4×12, about 480 screws, and roughly $225 of panels at $15 a sheet.
When to use this
- You are finishing a basement bedroom and need a sheet count the store can load in one trip, not a guess from the parking lot.
- A contractor's material list looks padded and you want to check the sheets and screws against the room you can measure yourself.
- You are deciding whether a taller ceiling pushes you into a second delivery once the ceiling panels are counted too.
- You are pricing a garage conversion and need the panel cost before tape, mud and finishing enter the conversation.
How to use it, step by step
- Measure the room length and width in feet, wall to wall.
- Enter the ceiling height — 9 ft ceilings add a lot more wall area than people expect over 8 ft.
- Say whether the ceiling is being boarded as well as the walls.
- Pick the sheet size you can actually get into the room, and set the price per sheet from your store.
- Read the sheet count for both sizes, the screw estimate and the panel cost together before ordering.
What the inputs mean
| Input | What it is | Typical values |
|---|---|---|
| Room length and width | The floor dimensions that set the wall perimeter and ceiling area | Bedrooms commonly 10 to 16 ft per side |
| Ceiling height | Wall height the perimeter is multiplied by | 8 ft standard, 9 ft common in newer builds |
| Ceiling included | Whether ceiling panels are added on top of the walls | Yes for a full finish, no for walls only |
| Sheet size | Panel coverage the count is divided by | 4 by 8 ft (32 sq ft) or 4 by 12 ft (48 sq ft) |
| Price per sheet | Your store's panel price, before tape and mud | $15 is the page default; check your local shelf price |
Another worked example
A 16 by 13 ft primary bedroom with 9 ft ceilings, ceiling included: the walls are 522 sq ft and the ceiling adds 208, for 730 sq ft to cover. In 4 by 8 sheets that is 23 sheets — about 736 screws and $391 in panels at $17 a sheet. In the other size it is 16 sheets of 4 by 12, fewer seams to finish but a much harder carry up the stairs.
Frequently asked questions
How many sheets for a 12 × 10 room with 8 ft ceilings?
Walls are 44 ft of perimeter × 8 = 352 sq ft; the ceiling adds 120, for 472 sq ft total. That is 15 sheets of 4×8 or 10 sheets of 4×12, roughly 480 screws, and about $225 in panels at $15 a sheet.
4×8 or 4×12 sheets — which should I buy?
4×12s mean fewer seams to tape and mud, but they are heavier, harder to move through halls and stairs, and near-impossible to hang solo on a ceiling. Most DIY rooms are 4×8 territory; pros with a lift reach for 12s.
How many screws does a sheet take?
About 32: screws every 12 inches in the field and 8 inches on edges at standard framing spacing. A 15-sheet room lands near 480 screws — buy the 5 lb box, not the 1 lb box.
Should I subtract doors and windows?
For sheet count, no — the sheet covering a doorway gets cut, and the offcut is rarely reusable elsewhere. The subtraction method saves at most a sheet and regularly leaves you one short.
🪵 Floor next?
The Flooring Calculator counts boxes with waste included — the same room, the other big surface.
What else do I need besides sheets and screws?
Joint tape, joint compound, corner bead, primer and paint are all separate from this count — the calculator prices panels only. The page's own advice stands on the sheets themselves too: order one or two spares on a real job, because returning an unopened sheet is cheaper than stopping work for one broken corner.
What if my room is not a simple rectangle?
Split it into rectangular sections — a main box plus the bump-out, closet bay or hallway stub — and run the calculator once per section. Add the sheet counts, not the room dimensions: combining an L-shape into one big rectangle boards over floor space that is not there and inflates the order.