To calculate the area of a room for carpeting, measure the width and length of the room, and multiply the width by the length. Calculate the width and length by measuring the room at the widest and longest sections of the room, including openings, such as bay windows.
In calculating the area of a room, measure all the way up to walls since the installer removes any molding during carpet installation. Add 10 percent to the area calculation to account for waste. Make measurements carefully to purchase all needed carpet at one time. Carpet colors may be slightly different for different production lots for the same brand and style of carpet.