Drywall Calculator
Enter your room's dimensions — the sheet and screw counts update as you type, and the link in your address bar always reflects your numbers.
How this calculator works
We add up the perimeter wall area — 2 × (length + width) × height — then subtract standard openings: about 21 sq ft per door and 15 sq ft per window, which cover typical residential door and window rough openings. Check "include ceiling" to add the floor's length × width on top, since a ceiling takes drywall too. The total area is divided by 32 sq ft (a 4×8 ft sheet, the most common size) and rounded up, because you can't buy part of a sheet. Screw count uses a commonly-cited rule of thumb of roughly 1.5 screws per square foot of drywall for standard 16"-on-center framing — treat it as a ballpark, not a stud-by-stud count.
Worked example
A 12×10 ft room with 8 ft walls, 1 door, and 2 windows, ceiling unchecked: wall area is 2 × (12 + 10) × 8 = 352 sq ft, minus 21 for the door and 30 for the two windows, leaving 301 sq ft. Divide by 32 and round up for 10 sheets. At roughly 1.5 screws per sq ft, that's about 452 screws. Turn on "include ceiling" and the 120 sq ft ceiling brings the total to 421 sq ft — 14 sheets and about 632 screws.
Frequently asked questions
Does this include the ceiling by default?
No — the ceiling is an optional checkbox you turn on. Ceilings are commonly measured and hung as a separate job from the walls: the sheets go up first (often 1/2" instead of the wall thickness), the fastening pattern is denser because gravity is working against you, and many people simply order wall and ceiling drywall in separate batches. Leaving it off by default keeps the base estimate matched to "walls only," which is the more common quick question.
Why does this calculator assume 4×8 sheets?
4×8 ft (32 sq ft) is by far the most common drywall sheet size at hardware and building-supply stores, so it's the safest default for a general estimate. Larger sheets — 4×12 and up — exist and reduce the number of seams you have to tape, but they're heavier and harder to maneuver alone into a room or up a stairwell. If you're planning to use a bigger sheet size, divide your total square footage by that sheet's area instead.
How much joint compound do I need?
That's intentionally out of scope for this tool. Joint compound quantity depends on how many coats you apply, how wide you feather your seams, and whether you're doing a basic level-3 finish or a smooth level-5 finish — factors this calculator has no way to know from room dimensions alone. Treat it as a separate estimate once you know your finish level.
Should I round up more for waste?
It's common practice to add extra sheets for irregular room shapes, lots of cuts around outlets and corners, or a first-time DIY job where mistakes are more likely. This calculator rounds each wall/ceiling area up to a whole sheet, but it doesn't add a separate waste buffer on top — if your room has unusual angles or you're less experienced with cuts, consider ordering one or two extra sheets.