Drywall Calculator
Estimate drywall sheets, screws, tape and joint compound for a room.
Supplementary Material List
Buying drywall means turning a room's dimensions into a sheet count — and then remembering the screws, tape, and joint compound that go with it. This calculator does all of that from the room's length, width, and height. Choose whether you're covering the walls, the ceiling, or both, set your sheet size and a waste allowance, and it returns the number of sheets to buy along with the fasteners and finishing materials. It runs entirely in your browser.
From room size to sheet count
The calculator first finds the surface area to cover, then divides by the area of one sheet and rounds up after adding waste:
Walls = 2 × (Length + Width) × Height • Ceiling = Length × Width • Sheets = ⌈(Area ÷ Sheet size) × Waste⌉
In "full room" mode it adds the ceiling and all four walls; the walls-only and ceiling-only modes use just the relevant part. A standard 4×8 sheet is 32 square feet, which is the default, and the waste multiplier — typically 1.10 for ten percent — covers offcuts and mistakes before the result is rounded up to a whole number of sheets, since you can't buy a fraction of a board.
Screws, tape and compound
The material estimates use common rules of thumb from the sheet count and area. Screws are figured at about 32 per sheet, a typical spacing for walls and ceilings. Joint tape is estimated at roughly one foot per square foot of drywall, which comfortably covers the seams in most rectangular rooms, and joint compound at about 0.35 gallons per sheet for taping and a couple of finishing coats. These are planning figures rather than precise counts — actual usage varies with how many seams and corners a room has and how smooth a finish you're after — so treat them as a shopping guide and round up when in doubt. The cost figure multiplies your sheet count by the price per sheet.
Frequently Asked Questions
Does it deduct doors and windows?
No. It calculates the full wall and ceiling area, which is the conservative approach — the openings effectively become part of your waste allowance and give you spare material for mistakes and offcuts.
What sheet size should I choose?
A standard 4-by-8-foot sheet is 32 square feet and is the default. If you are buying 4-by-12 or another size, set the sheet area accordingly so the count comes out right.
How accurate are the screw, tape and compound figures?
They are industry rules of thumb — about 32 screws and 0.35 gallons of compound per sheet, and roughly a foot of tape per square foot. Rooms with more corners and seams use more, so round up when buying.
Is anything I enter saved?
No. The calculation runs in your browser and nothing you type is uploaded or stored.