Drywall Calculator
Drywall Calculator works out Panels to buy and Net area covered from Room length, Room width and Wall height. The default figures on this page give panels to buy of 16; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
7 steps
- Area: walls 2 x (16 + 12) x 8 = 448 sq ft = 448 ft2.
- Panel: 4 ft x 8 ft (32 sq ft) = 32 ft2.
- With 10% waste: 448 x 1.1 = 492.8 ft2.
- Panels = ceil(492.8 / 32) = 16.
- Screws: 7 framing members across 96 in at 16 in o.c., 4 screws down each at 16 in o.c. = 28 per panel, 448 in total.
- Tape: half the perimeter of each panel, 12 ft x 16 = 192 ft.
- Cost: 16 x 18 = 288 in panels, plus 448 sq ft x 0 = 0 labour = 288.
Its 4 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the Drywall Calculator calculates
Counts the drywall (sheetrock / gypsum wallboard) panels a room needs from its dimensions or net area, then the screws, joint tape, joint compound and the installed cost at your own material and labour rates.
How to use this Drywall Calculator
Enter Room length, Room width, Wall height and Unit for the room dimensions. Panels to buy updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Panels to buy, Net area covered and Area of one panel.
The method follows ASTM C1396/C1396M, Standard Specification for Gypsum Board, Gypsum Association GA-216, Application and Finishing of Gypsum Panel Products and Researched engineering contract R376 (DRYWALL-SHEETS).
12 ft x 14 ft room, 8 ft walls, 4x8 panels, 10 percent waste example
With Room length: 12, Room width: 14, Wall height: 8, Waste allowance: 10, the calculator returns Net area covered: 416, Panels to buy: 15, Area of one panel: 32. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Panels to buy, Net area covered and Area of one panel. The inputs you can vary are Room length, Room width, Wall height, Unit for the room dimensions, Board the ceiling as well and Area of doors and windows.
Understanding Panels to buy, Net area covered and Area of one panel
A materials take-off only. Fire-rated, shear and moisture-resistant assemblies have prescriptive requirements for panel type, thickness, fastener pattern and joint treatment that must be taken from the tested assembly listing and the code adopted where you build.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do I calculate how much drywall I will need?
Counts the drywall (sheetrock / gypsum wallboard) panels a room needs from its dimensions or net area, then the screws, joint tape, joint compound and the installed cost at your own material and labour rates. Open “How this is worked out” beside the result to see each step for your own figures.
Is there a good app for drywall estimating?
Counts the drywall (sheetrock / gypsum wallboard) panels a room needs from its dimensions or net area, then the screws, joint tape, joint compound and the installed cost at your own material and labour rates. On the figures this page opens with — room length 12, room width 14 and wall height 8 — the panels to buy is 16. Put your own figures in their place and the working updates beside the result.
How do I calculate how much drywall compound I need?
It needs Room length, Room width, Wall height, Unit for the room dimensions, Board the ceiling as well and Area of doors and windows. Nothing else is required, and the figures stay in your browser.
What information do I need for the Drywall Calculator?
You need Room length, Room width, Wall height, Unit for the room dimensions, Board the ceiling as well, Area of doors and windows, Net area to cover (overrides the dimensions) and Area unit. The page opens with default figures that give panels to buy of 16, so you can see the scale before entering your own.
What does this Drywall Calculator show?
It shows Panels to buy, Net area covered, Area of one panel, Area including waste, Panels before the waste allowance, Screws per panel, Screws and Joint tape, with the working and any warnings for your entries.
Can I check how the Drywall Calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.