According to the Lester Carpet Company, running feet of carpet is calculated by selecting which direction the carpet will be unrolled during installation and measuring how many rolls will fit into a room in that direction. The length of the room in the direction of the unrolling is called the "run," which can be measured in feet.
Lester Carpet Company suggests calculating the running feet you'll need for a project before carpet is professionally installed to double-check the technician's work and protect the homeowner from surprise costs. The easiest method is to begin by drawing a rough sketch of the room's floor plan in a way that is easy to read. Next, measure the length and width of the rooms from wall to wall, recording the measurements onto the sketch. Make sure that all of the recorded measurements use the same measurement units, typically feet. Once each room is measured, multiply the length of each room by the width of the same room to get the square units. Adding all of these numbers together will give the total square units. Be aware that a square unit must be divided by another square unit to convert between inches, feet and yards.