Drywall Calculator
Calculate drywall sheets plus joint compound, screws, and tape - by room size, with door and window deductions and an optional ceiling.
Wall perimeter is calculated automatically from length and width.
How to Use
- Enter room length and width - the calculator finds the wall perimeter automatically.
- Enter wall height - 8 ft is standard; 9–10 ft walls suit 4 × 12 sheets to cut down on butt joints.
- Pick the sheet size - bigger sheets mean fewer seams but are heavier to handle.
- Add ceiling and openings (Advanced) - toggle the ceiling and enter doors and windows to deduct.
- Set waste - 10% for a standard room, 15% for small rooms with many cuts.
A 12 by 12 room with 8 foot ceilings needs 14 sheets of 4x8 drywall for the walls: 384 square feet before waste, or 19 sheets if you board the ceiling too. For the 384 square feet of wall board, this planning model returns about 4 gallons of joint compound, 423 screws, and 143 linear feet of joint tape. Enter your room size above; door and window openings are deducted automatically.
How the Sheets Hang
How Much Drywall Do I Need?
Start with the wall area - the room perimeter times the wall height - then subtract the doors and windows, add the ceiling if you are hanging it, add a waste factor, and divide by the coverage of one sheet. A 4 × 8 sheet covers 32 square feet, a 4 × 10 covers 40, and a 4 × 12 covers 48. This calculator does all of that and rounds up to whole sheets.
But sheets are only part of the order. Hanging drywall also needs joint compound, screws, and tape, and the simple "sheets only" calculators leave those out - which is the single most common reason people make a second hardware-store trip. This tool estimates all three alongside the sheet count. It also includes an optional price-per-sheet field for a quick materials cost - and when you want the full installed price including labor, our drywall cost calculator estimates that by finish level and region.
Bigger sheets create fewer seams to tape and finish, so 4 × 12 panels are popular on 9- and 10-foot walls. They are heavier and harder to maneuver, though, so most DIYers stick with 4 × 8.
Drywall Materials Per Sheet
Beyond the panels themselves, the calculator uses manufacturer-style estimating allowances for finishing materials. Actual product coverage and fastening schedules still control the final order:
| Material | Rule of thumb | How it is sold |
|---|---|---|
| Joint compound | ~10 gal per 1,000 ft² | Product/package size varies |
| Screws | ~1 per ft² (32 per 4×8 sheet) | 1 lb (~320) and 5 lb boxes |
| Joint tape | ~370 linear ft per 1,000 ft² | Commonly sold in rolls |
| Corner bead | 1 stick per outside corner | 8 ft and 10 ft lengths |
The compound and tape allowances are planning estimates based on common manufacturer estimating data. Product type, finish level, layout, seam count, waste, and installer technique can change actual consumption.
Sheets by Room Size (8 ft walls, 4×8 sheets, walls only)
| Room (ft) | Wall area | 4×8 Sheets (10% waste) |
|---|---|---|
| 10 × 10 | 320 ft² | 11 |
| 12 × 12 | 384 ft² | 14 |
| 12 × 16 | 448 ft² | 16 |
| 16 × 20 | 576 ft² | 20 |
Before door/window deductions. Add the ceiling (length × width) if you are hanging it.
Drywall Formulas
The room-based method:
Less openings = − 21 ft² per door − 15 ft² per window
Ceiling (opt.) = length × width
Sheets = (net area × (1 + waste)) ÷ sheet coverage, rounded up
Joint compound = ≈ area ÷ 100 gallons (about 10 gal per 1,000 ft²)
Screws = ≈ area × 1.1 screws/ft² as a rough planning allowance
Joint tape = ≈ area × 0.37 linear ft/ft²
Sheet coverage is 32 ft² (4×8), 40 ft² (4×10), or 48 ft² (4×12). Materials are estimates for a standard three-coat finish; textured or Level 5 finishes use more compound.
Code Notes & Sources
- The type of gypsum board and how its fasteners are spaced is governed by IRC Table R702.3.5 - screws land closer at the sheet edges and the seam than in the field, which is why the calculator plans about one fastener per square foot. Ceilings and fire-rated assemblies use tighter spacing.IRC 2021 Table R702.3.5 - Gypsum Board Application and Fastening
- USG estimating guidance lists about 370 linear feet of joint tape and roughly 10 gallons of all-purpose joint compound per 1,000 square feet of gypsum panels as material-estimating quantities. Actual use varies with product, finish level, layout, and workmanship.USG - Sheetrock Gypsum Panels Installation Guide
Next Steps
Board counted, plan the wall around it:
Related Calculators
Drywall goes up after framing and before paint - see the full surface calculator collection.
Frequently Asked Questions
How do I calculate how much drywall I will need?
Multiply the room perimeter by the wall height to get the wall area - that is 2 × (length + width) × height. Subtract about 21 square feet per door and 15 per window, add the ceiling (length × width) if you are hanging it, then add 10% for waste and divide by the coverage of one sheet: 32 square feet for a 4×8, 40 for a 4×10, or 48 for a 4×12. Round up to whole sheets. The calculator above does all of this and adds the compound, screws, and tape.
How many sheets of drywall for a 12x12 room?
A 12×12 room with 8-foot walls has about 384 square feet of wall. With 10% waste and 4×8 sheets, that is 14 sheets for the walls. Add the ceiling (144 ft², about 5 more sheets) if you are hanging it, and subtract roughly 21 ft² per door and 15 per window.
How many sheets of drywall for a 1500 sq ft house?
A 1,500-square-foot home has roughly 4,500 square feet of drywall to cover - about three times the floor area, once you count every wall and ceiling. With 4×8 sheets and a 10% waste factor, that is around 140 to 160 sheets, depending on your layout, ceiling heights, and number of interior walls. Calculate each room above and total the sheets, then use our drywall cost calculator to price the installed job.
How many square feet is a 4x8 sheet of drywall?
A 4×8 sheet of drywall covers 32 square feet (4 feet × 8 feet). A 4×10 sheet covers 40 square feet and a 4×12 covers 48. To estimate sheets, take your total drywall area, add about 10% for waste, and divide by the sheet coverage - so a 400-square-foot room needs about 14 sheets of 4×8.
How much joint compound and tape do I need?
For planning, this calculator uses about 10 gallons of joint compound and 370 linear feet of tape per 1,000 square feet of drywall. Those are estimating allowances, not guaranteed package yields. Finish level, product, layout, seam count, waste, and installer technique can change actual consumption.
How many screws per sheet of drywall?
About one screw per square foot, which works out to roughly 32 screws for a 4×8 sheet - one every 12 inches in the field and every 8 inches along the edges. A 1 lb box holds around 320 screws, and a 5 lb box covers roughly 30 sheets. Use 1¼-inch screws for ½-inch drywall on wood studs.
Should I use 4x8 or 4x12 sheets?
Use 4×8 sheets for easier handling, especially solo or in small rooms. Use 4×12 sheets on longer or taller walls (9–10 ft) to reduce the number of seams you have to tape and finish, which gives a flatter wall - but they are heavy and usually need two people.
Do I drywall the ceiling or walls first?
Hang the ceiling first, then the walls. The top wall sheets then push up against the ceiling sheets and help support their edges, and the seam ends up easier to finish. Ceilings need more screws and often a panel lift or a helper.
Is there a free drywall calculator app?
You do not need to install an app - this drywall calculator runs free in your browser on any phone, tablet, or computer, with no signup or download. Enter your room size and it returns the sheet count plus the joint compound, screws, and tape you will need. Bookmark it and it is there whenever you need a quick estimate.