Enter a room's length, width, ceiling height, and door/window openings once and get floor/wall area, drywall sheets, insulation coverage, and paint gallons together.
An interior remodel almost always touches drywall, insulation, and paint over the same room footprint. This page runs Room Layout once to get floor area, wall area, and perimeter, then feeds that straight into the Drywall, Insulation, and Paint calculators. Each calculator below is the same one available on its own page — nothing here is a new formula, it is Room Layout’s output read the same way Drywall/Insulation/Paint already read a shared room layout on their standalone pages.
Drywall sheet count is wall area plus ceiling area, divided by the coverage of one sheet, with a waste allowance rounded up to a whole sheet — the same math as buying fixed-size sheets from the yard. Wall area here comes directly from Room Layout’s perimeter times ceiling height, minus door and window openings, so changing the room’s length, width, or ceiling height updates the drywall count automatically.
Standard sheets are 4x8 ft, but 4x12 sheets are common on taller walls to cut down on horizontal seams. Waste accounts for cuts around outlets, corners, and openings.
Enter room length, width, ceiling height, and openings once. Drywall, insulation, and paint each add a few fields of their own below (sheet size, target R-value, coverage rates) that a room's dimensions alone don't determine.
Floor area, wall area, and perimeter from room length, width, and ceiling height — the shared backbone for Drywall, Insulation, and Paint below.
This room has — sq ft of wall and — sq ft of floor.
This room has
The shoelace (surveyor's) formula for the area of a simple polygon, wrapping the last vertex to the first; the perimeter is the Euclidean distance summed around that same closed list. Both are mathematical identities -- no trade convention and no published source stands behind either, and none is needed.
Drywall sheets to buy from the room's wall and ceiling area, sheet size, and waste percent.
You'll need — sheets of drywall for — sq ft.
You'll need
Half of each sheet's perimeter, because a seam is the shared edge of two sheets and the whole perimeter would count it twice. Runs short on a single-sheet patch and converges on a full room -- see the derivation in drywall.ts. Joint compound, corner bead and screws are not counted.
Coverage units or cavity volume and delta R-value for the room's walls.
You'll need insulation of insulation for — sq ft.
You'll need
Coverage per bag is depth-dependent. The divisor must be the figure for the R-value being installed, not the headline coverage on the bag.
Primer and topcoat gallons for the room's wall area.
You'll need — gal of paint to cover — sq ft.
You'll need
Insulation on this page can be estimated two ways: by cavity depth and an R-per-inch rating for the product, or by entering a known R-value directly. Delta R (target minus current) shows how much more insulating value the wall needs to reach code or design targets — a wall already at or above target doesn’t need more.
Coverage area for insulation is the room’s wall area from Room Layout, the same area feeding Drywall, since insulation typically goes into the same wall cavities being closed up with drywall.
Paint gallons divide wall area by a coverage rate (typically 300-400 sq ft per gallon, but check the product label) and multiply by the number of coats, rounding up to a whole gallon. Primer is optional and uses its own coverage rate — skip it on previously painted walls in good condition, or keep it on for bare drywall, patched areas, or a major color change.
This page paints wall area only, not the ceiling — a common scope for a room repaint versus a full gut remodel. If ceiling paint is part of the job, add its area to the topcoat gallons separately.
Floor area, wall area, and perimeter are useful numbers on their own when scoping a remodel, so this page shows the Room Layout result directly, the same as the standalone Room Layout calculator, in addition to feeding Drywall, Insulation, and Paint below it.
No, this page paints wall area only. If the job includes ceiling paint, add the ceiling area to the topcoat gallons separately or use the standalone Paint calculator with a combined area.
Yes. Flip any section to "Manual entry" to edit its inputs directly without changing the room layout or the other calculators.
List each opening as width x height in inches, separated by commas — for example "36x80, 36x48" for a standard door and a window. Feet still work if you mark them, so "3'x6'8\"" reads the same as "36x80".
Material estimate and general reference only. Verify local code, manufacturer coverage rates, and field conditions before ordering or starting work.