Drywall Calculatorv1.0.0

Drywall quantity comes down to one number: the net square footage of board you have to hang, divided by the coverage of a single panel. This calculator builds that number from as many rooms or surfaces as a job contains, subtracts the openings you list, adds a waste allowance, and rounds up to whole panels. Every area entry is independent, so a basement with three differently sized rooms and a stairwell wall can be estimated in one pass.

• Pick your Measurement units first. Feet is the default. Switching units converts every value already entered rather than reinterpreting it, so a 12 that meant feet becomes 3.6576 when you switch to meters.
• For each area, choose a method. Length x Width x Height treats the entry as a room: wall area is 2 x (Length + Width) x Height. Tick Include ceiling to add Length x Width on top of the walls. Leave Height blank and the entry becomes a single flat rectangle of Length x Width, which is how you enter one wall, one ceiling, or a soffit face.
• Choose Square footage instead when the area is already known from a plan or a takeoff. The value is read in the squared version of the selected measurement unit, so square meters while Meters is selected.
• Open Doors and windows to deduct on an entry to remove openings. Enter a count and the size of one opening; the calculator multiplies them. Defaults are a 3 by 6.75 foot door and a 3 by 4 foot window. Leave the counts at zero to hang board across the full wall and cut the openings out afterward, which is what many installers do when the cutout becomes scrap anyway.
• Give an entry a Name if it helps you read the per-area breakdown, such as Master Bedroom or Stairwell. The field is optional; a blank name reports as Area 1, Area 2, and so on.
• Use Duplicate on any entry to copy its values into a new entry directly below, which is faster than retyping four bedrooms of the same size. Delete removes a single entry and leaves the others untouched.
• Set the Panel size to match what your supplier stocks. Thirteen standard sizes are listed, from 4 by 8 feet through 4 by 16 feet, including the 54 inch wide sheets sold for 9 foot walls. Choosing Custom size reveals a width and length pair directly below the dropdown; both are read in feet because board is sold in imperial sizes whatever measurement unit you entered the rooms in.
• Set the Waste allowance. Ten percent is a common starting point for a straightforward room. Raise it for rooms with many openings, angles, or short runs, or set it to zero to see the bare requirement.
• Enter a Cost per panel to get a material subtotal. The total multiplies the rounded panel count, not the fractional one, because you buy whole sheets.

Formulas in plain text: Wall area = 2 x (Length + Width) x Height. Ceiling area = Length x Width. Openings = (door count x door width x door height) + (window count x window width x window height). Net area = Gross area - Openings. Panels to buy = ceiling(Net area x (1 + Waste / 100) / Panel area). All numeric fields accept decimals (0.75), fractions (3/4), mixed numbers (5 1/16 or 1-3/8), and scientific notation (1.5e3), and currency symbols, commas, and percent signs are stripped before parsing.

Drywall is bought in whole sheets and delivered in a single drop, so the cost of guessing runs in both directions: a short order stops the job for a supply run, and a long order leaves sheets warping against a garage wall. The scenarios below cover the takeoffs this calculator is shaped for, from a single patch wall to a whole floor of a house.

• Single room remodel: One entry, Length 12, Width 10, Height 8, ceiling included, one door and one window deducted. At 4 by 8 foot panels with 10 percent waste that returns 439.75 square feet net and 16 panels.
• Whole floor takeoff: Add an entry per room, duplicate the repeated bedroom sizes, and read the per-area breakdown to see which room drives the order. The breakdown reports gross, openings, net, and panels for each entry separately.
• Garage or shop with tall walls: Select 4 by 12 or 4 by 16 foot panels so a 10 or 12 foot wall hangs in a single vertical sheet, then compare the panel count against 4 by 8 to see how many butt joints the longer sheet removes.
• Ceiling only: Choose Length x Width x Height, enter the room length and width, and leave Height blank. The entry becomes a flat rectangle, which is the ceiling area on its own.
• Fire rated or moisture rated assemblies: Estimate the board area first, then confirm the required thickness and layer count with local code. A two layer assembly needs the panel count doubled, which the calculator does not do for you.
• Contractor quoting: Enter a cost per panel from a current supplier sheet and switch the currency to match the quote. The material subtotal updates as the waste allowance changes, which makes it quick to show a client the difference between a 5 percent and a 15 percent allowance.
• Metric plans: Set units to meters and enter room dimensions straight off a metric drawing. Panel sizes stay imperial because that is how board is sold in North America, and the net area is reported in square feet, square meters, and three other units.
• Finishing material budget: Open the fasteners and finishing section for screw count, screw weight, joint compound buckets, and tape length derived from the net board area, with every rate exposed and editable rather than fixed.
• Repair and patch work: Use Square footage to enter a measured patch area directly, set waste to zero, and see whether the repair takes one sheet or two.