Drywall Calculator

How to use

1. 1Pick units (feet and inches or meters) and the sheet size your local supplier carries.
2. 2Set the waste allowance with the slider. 10 to 15 percent is typical for hardwoods; bump higher for irregular rooms with cathedral or vaulted ceilings.
3. 3Optional: adjust the door and window opening sizes if yours are not the 3 ft x 6 ft 8 in door and 3 ft x 4 ft window defaults.
4. 4Type each room's length, width, and ceiling height. Set the door and window counts. Toggle Include ceiling if you are hanging drywall on the ceiling too.
5. 5Use Add room to add more rooms, or switch a row to Custom area for an accent wall, soffit, or already-measured surface.
6. 6Read the totals card for sheets needed, joint tape, compound, and screws. Optional: turn on Estimate cost, enter the price per sheet, and pick a currency.
7. 7Use Copy summary for a shopping list, or Copy CSV to drop the per-room breakdown into a spreadsheet.

About this tool

Drywall Calculator estimates the number of drywall sheets (also called sheetrock, gypsum board, wallboard, or plasterboard) you need to wall and optionally ceiling one or more rooms, plus the joint tape, joint compound, drywall screws, and total sheet cost. For each room you type length, width, and ceiling height and the tool computes the wall area as 2 x (length + width) x height, optionally adds the ceiling area (length x width), and subtracts a deduction for each door and each window. The deductions default to a standard 3 ft x 6 ft 8 in interior door (21 sq ft) and a 3 ft x 4 ft window (12 sq ft), and both sizes are configurable with custom widths and heights so larger sliding doors, picture windows, and arched openings can be accounted for. The sheet picker covers the four common North American sizes (4 x 8 ft, 4 x 9 ft, 4 x 10 ft, and 4 x 12 ft) plus the European metric standards (1200 x 2400 mm and 1200 x 3000 mm), and the waste-allowance slider adds 0 to 30 percent on top (10 to 15 percent is typical for rectangular rooms with simple corners; 20 percent is safer for cathedral ceilings or rooms with many short pieces). The result rounds up to whole sheets because drywall is sold by the sheet, never in pieces. Materials are estimated from industry rules of thumb: 0.4 linear feet of paper joint tape per square foot of drywall, 0.053 lb of all-purpose joint compound per square foot (for taping plus three coats), and roughly 1.125 #6 drywall screws per square foot at standard 16 in framing spacing, plus an equivalent number of 4.5-gallon (61.7 lb) premixed buckets and 18-kg dry powder bags for shopping. A custom-area mode handles attic kneewalls, accent walls, soffits, and any single measured surface where you already know the square footage. An optional price-per-sheet input in eight currencies (USD, EUR, GBP, CAD, AUD, JPY, INR, TRY) yields the total sheet cost. Copy summary lifts a one-paragraph plan and Copy CSV exports the per-room breakdown for a spreadsheet. Useful for homeowners pricing a basement finish, contractors quoting a hangup job, landlords budgeting between tenants, garage and shop conversions, and any moment when you would otherwise multiply room dimensions on a notepad. Everything runs locally in your browser; nothing about your home is uploaded.

Free to use. Works in your browser. No signup, no login.