This calculator requires the use of Javascript enabled and capable browsers. This program will calculate the amount the amount of sheetrock needed to drywall an area or a room. The term sheetrock refers to gypsum board. It comes in various sizes, thicknesses and qualities. The terms green or wet rock refers to a special variety used in bathrooms and indoor spas. As a general rule, 4x8 sizes are used in most residential applications, while 4x9, 4x10 and 4x12 are usually used in commercial applications. They are also much more difficult to handle, especially for one person. Before you begin, take the room measurements for the data entry. If you have sloping walls, follow the special case instructions on how to determine this square footage. For wall height, measure from floor to ceiling. For wall perimeter of the areas you plan to drywall, measure the length of each wall. Add all length figures together to obtain the total horizontal distance, or perimeter of the wall structure. If you are drywalling the ceiling, measure the width and length, usually easiest to do by measure the floor under it. You may omit this if you do not plan to drywall the ceiling. Accumulate the measurements of all excluded sections by measuring the height and width of each area separately and adding all widths into one total and all heights into a second total. Sloping walls form a triangular wall space. To calculate a triangle’s square footage, multiply the length of the wall at the base of the triangle by its height and divide by 2. If you wish to get an approximate cost of the sheetrock, enter the cost of one drywall sheet of the size you plan to use; you may leave this a zero if you are not interested in the price. Enter all of the other values in the appropriate areas. Click the Calculate button for all fields to be calculated; at least ONE value for drywall is required. The entry fields are color coded in ocean blue, while the results are in light blue. The values returned are the number of drywall sheets needed and the total cost of them, based on your entry of measurements and cost per board. Descriptive fields are in yellow. The salmon colored fields either show what action is taken to entries or requires action on your part. To do another, click the Clear Values button and then enter a new set of values. You may also wish to just change certain fields and recalculate. Calculated accuracy of current Javascript enabled browsers is generally 16 places, however, these results are rounded to make life easy.