Drywall calculator

Calculator to estimate how many gypsum boards to buy for the project.

Input parameters
Room dimensions
Room 1
Room 2
Room 3
Room 4
Room width W1
Room length L2
Ceiling height H3
Substractions (Sq. Ft.)4
Waste factor5
Drywall size
Drywall dimensions (feet)

Computed parameters
Room 1
Room 2
Room 3
Room 4
Total area(s) square footage6
Sq. Ft. Sq. Ft. Sq. Ft. Sq. Ft.
Number of gypsum panels to buy7
Drywall screws8 - Number
Weight (lb)
Joint compound9 Weight (lb)

Drywall calculator estimates total installation area dimensions, amount of gypsum boards, drywall screws and joint compound which are necessary to purchase to complete the project based on room dimensions, ceiling height and drywall panels size.

By default, calculator computes parameters for up to four rooms including installation of drywall in average size bedroom with standard single window and one door, bigger living room with larger walkway opening in the wall, medium size office and typical walk-in closet. All input parameters can be adjusted based on exact room measurements and drywall panel dimensions.

Input parameters

1 W – width of room in feet. Inches values should be entered as real number means 3 inches = 0.25 feet; 6” = 0.5’; 9” = 0.75’ and so on.

2 L – length of room in feet. Input real numbers only.

3 H – ceiling height in feet or distance between subfloor and ceiling joists excluding thickness of gypsum panels and flooring.

4 In subtractions should be included all doors, windows, skylights and other walls or ceiling openings not covered by drywall. For example for each 32x80 pre-hung door you must subtract 17 ft2, for each 28x54 window subtract 10 ft2 and so on.

5 For majority of basic drywall installation projects 15% waste factor is an average. In some cases waste factor cold be reduced. For example, if room dimension are 10W x 10L x 8H exact and you will buy 4x10 gypsum panels waste could be 10% or even 5% depending on doors and windows placement. For complicated tasks waste of gypsum boards could go up to 35%, very rare even higher.

Computed parameters

6 Total square footage is and actual walls and ceiling area where drywall panels should be installed excluding all subtractions.

7 Actual number of gypsum boards to buy including waste factor.

8 Number of drywall screws estimated accounting putting screws every 12 inches in the field of a panel in each wall stud and ceiling joist placed 16 inches apart, and every 6 - 8 inches in the top framing plate and corners. Weight calculated based on using 1-5/8 in. long screws accounting 200 screws per pound. 10% extra was added for a waste und unplanned usage.

9 Joint compound estimated based on purchasing All-Purpose Pre-Mixed Joint Compound with coverage approximately 11 Sq. Ft. per each lb. Additional 15% added for unplanned consumption and waste.

Gypsum boards calculator is for a general purpose only and computes parameters with high accuracy for basic projects. While installing drywall on multileveled, tray, coved, cathedral ceiling, arches or custom designed walls consumption of materials will increase significantly. For partial repair or custom drywall project amount of materials to buy could be estimated only after blueprint analysis or on-site inspection.