Access Panel Cutout Area Deduction Calculator
Calculate net drywall/plasterboard area after deducting access panel cutouts.
Materials & Quantities
Board, plaster and the framing and fixings behind them.

Board counts, screws and adhesive; corner bead, trim and texture; joint backing and kerf cuts; plaster in scratch, brown and finish coats; shaftwall with its J-track and liner; suspended and direct-fixed ceilings; acoustic treatment from resilient channel to mass-loaded vinyl; and the fire-rated assemblies — layer counts, firestopping, intumescent coating.
Whether the assembly has a rating to meet. An unrated partition is an area problem: board, screws, tape, compound. A rated one is an assembly problem, and the layer count, screw spacing and joint treatment all come from the tested detail rather than from the quantity — which is why those calculators ask for the rating first and name the assembly they are reading.
The structural framing behind a loadbearing wall, the insulation in the cavity, and the paint on the finished surface.
42 calculators
Calculate net drywall/plasterboard area after deducting access panel cutouts.
Calculate the number of suspension wires needed to hang an acoustic ceiling cloud or baffle panel.
Calculate the specular reflection point and incidence angle for a flat acoustic reflector panel, using the image-source method.
Calculate the acoustic sealant volume needed to seal the perimeter of a soundproofed wall or ceiling assembly.
Calculate how many control joints are needed to break up a large drywall ceiling run within a maximum unbroken span.
Calculate how many gypsum board sheets are needed to fasten directly to a ceiling's framing, with waste allowance.
Calculate how many splice connections are needed to join standard-length main runners across a suspended ceiling run.
Wall angle for a suspended ceiling's perimeter, waste included, and the stock lengths to order once every corner is counted as a run of its own.
Check a cold-formed steel stud's calculated lateral (wind) deflection against a code deflection limit.
Calculate the number of cold-formed steel studs needed for a wall run at standard 16 or 24 in (400 or 600 mm) on-center spacing.
Calculate total self-tapping screws needed to fasten cold-formed steel studs to top and bottom track.
Calculate how many bullnose corner bead segments are needed to follow a curved wall's radius.
Calculate the drywall adhesive needed to dot-and-dab plasterboard directly onto a masonry wall, and the bags it comes to.
Calculate the total backing/blocking length needed behind unsupported drywall butt joints.
Calculate total screws needed for a ceiling drywall installation at its (typically tighter) code-required fastening spacing.
Calculate total corner bead needed for a project's outside drywall corners, with waste allowance.
Calculate how many kerf cuts are needed along a drywall sheet to let it bend around a curved wall.
Calculate the laminating adhesive needed to bond a second layer of drywall directly to a base layer.
Calculate total drywall screws needed per sheet from separate perimeter and field fastening spacing, then scale to your sheet count.
How many cartridges of construction adhesive it takes to board a stud wall at your bead size and stud spacing, and the field fasteners alongside.
Calculate the texture compound needed to spray-finish a drywall wall or ceiling area.
Calculate total J-bead or L-bead edge trim needed for exposed drywall edges, with waste allowance.
Undercoat and finish plaster for a masonry wall, as two separate bag counts — because the two coats are different products at very different densities.
Calculate the total number of anchors needed for a hat channel furring system on a wall or ceiling.
Calculate total top and bottom track length needed for a cold-formed steel stud wall run.
Calculate the mass-loaded vinyl material needed for a wall or ceiling soundproofing barrier, with waste allowance.
Estimate an approximate STC rating for a multi-layer stud wall assembly from an additive rule-of-thumb point system.
Angle and stop beads counted in whole stock lengths, because a bead cannot be joined mid-run — with the offcut shown rather than hidden in a percentage.
Calculate the plaster volume needed for a brown (leveling) coat, the second layer of a three-coat plaster system.
Calculate the plaster volume needed for the thin finish coat, the final layer of a three-coat plaster system.
Calculate the plaster volume needed for a scratch (base) coat over lath.
Binder and sand for each coat of a render or plaster build-up, at the coat thicknesses the system sets, each coat weaker than the one beneath it.
Calculate the number of rows and total linear footage of resilient channel needed for a decoupled soundproof wall or ceiling.
Calculate total screws needed to fasten resilient sound-isolation clips and furring channel.
A room's reverberation time (RT60) by Sabine, from its size and each surface's absorption coefficient, and the absorption or absorber a target time needs.
Calculate total J-track length needed for a shaftwall run, with waste allowance.
How high a C-H shaftwall stud runs unsupported at a given spacing and pressure before its deflection limit, and the share of it a proposed height uses.
Calculate total self-tapping screws for a shaftwall stud run, from the fastening schedule your tested assembly actually specifies.
Calculate the number of shaftwall (CH/CT) studs needed for an elevator or mechanical shaft wall run.
Bags of finish plaster to skim a plasterboard wall or ceiling, from the area and the finished thickness the background actually needs.
Calculate the total drywall area needed to wrap a boxed-in soffit or bulkhead (two side faces plus the bottom face).
Calculate the number of suspension wire hangers needed for a drop ceiling grid at standard spacing.