Calculate How Much Carpet is Needed for Stairs

The staircase is one of the most prominent features of a home or office. And depending on its location, it may also be the most trafficked structure as well. Most modern staircases come carpeted. This carpeting not only preserves the shine of the wooden base material, but it also adds color and vivacity to the general ambience of the home or office.

Carpets are installed either by professional carpet service staff or by yourself, If you do decide to do-it-yourself about installing a carpet on your staircase, it is important you accurately determine how much carpeting is required to fit your staircase perfectly. Stairs come in different shapes, dimensions and sizes. At this point, it might help to know the kinds of stairs that can be found in most homes and offices. They include the following:

Types of Stairs:

Box Stairs

A Box stair is typically straight with no railings or posts, and it is enclosed. The Box Stairs is 3 inches wide on its tread.

Cap Stair

A Cap Stair features railings and is open on one side.

Pier Stair(Winder)

A Pier Stair has a curved structure.

Open Stair

An Open stair comes with no backing.

The parts of the staircase that receive your carpet includes the Tread ( the flat part your feet step on) and the Riser( the back of the stairs). With these features in mind, you can compute the amount of carpeting you need for your staircase.

Obtaining the correct amount of carpet you need, not only saves you time and money, but such a process can also serve as an important precursor to the actual installation itself. The following steps can help you compute the amount of carpet required for your staircase:

Process to Calculate Required Amount of Carpet for Stairs

Step 1

Determine the dimensions of the stair tread.

Measure the tread from one end of one side to the other. In this case, you will measure from the wall to the railings or post. If you come up with fractions in your dimensions, the rule of thumb is to round up to the nearest inch or meter.

Step 2

Measure the dimension of the riser. You will take the dimensions of the tread in the opposite direction to your previous measurement. In this instance you will get the dimensions of the tread lengthwise besides the dimension of the riser (the height of each staircase). Again, you are to round-off your computations to the nearest inch or meter.

Step 3

The base dimensions for your staircase have been determined. Most carpeting processes use padding to provide a snug finish to the carpeting. It also offers protection for users. If you are placing strips of padding underneath your carpet, give an allowance of over 3 inches or 0.08 meters. This step is necessary as your carpet’s padding needs to be accommodated.

Step 4

Compute the dimensions for the tread and the riser, adding the allowances for each measurement. Multiply these new dimensions to get the area of the one staircase, either in square inches or meters. This is the area for one step on your staircase.

Step 5

The next information required is the number of steps or stairs that makes up your staircase. Depending on the size and structure of your home, the number of steps or stairs could be between 12 to 20 steps. Multiply the number of steps by the square area (in inches or meters), to give the total square area or footage for the carpeting of your staircase.

Step 6

You have determined the total square area of your staircase. The next action is to convert this number into the amount of carpet material needed for your staircase. You can either use an online carpet calculator or you could divide by a number corresponding to the unit of measurement (inches or meters). If you have a total dimension in square feet, then you are to divide the figure by 9, to give you the amount of carpet needed in square yards.

Pile Direction

The best carpet for stairs must run in the same direction on every stair. It is also important that the carpet is laid in the direction of the flow of traffic. In this case, place your carpet from top to bottom and not from side to side.


Getting your staircase carpeted can a tricky task. You have to take into consideration the unique features of your staircase. A god number of staircases range between 12 to 20 stairs. Some configurations split into 6 to 7 flight steps, with a landing at the mid-point and at the base of the staircase. These landings must also form an important part of your measurements.

Conventional wisdom dictates that you buy extra carpet material, to accommodate any mistakes that may arise during the actual carpeting process.