Stair Carpet Calculator
You're probably looking for something that you can put two or three numbers into and come up with the total amount of carpeting, but that's not what we're going to provide you with. We are going to provide you with a few different ways to calculate the amount of carpeting you need for your stairway and let you figure it out by yourself.
How To Calculate The Amount Of Stairway Carpeting You Will Need To Carpet Your Stairway?

Step One: Measure the width of the stairway.

Step Two: Measure the individual height of one riser.

Step Three: Measure the individual width or depth of each stair tread.

Step Four: Count the amount of individual stair treads and risers.
Step Five: Add your total stair tread and riser measurements up, to create the length of your stairway and multiply this number by the width and then convert it into square yards.
For example, if I had 13 stair treads at 11 inches each, I would simply
multiply 13 x 11, providing me with a total of 143 inches. Then I would
multiply the total amount of risers, by the individual riser total
height. 14 risers times 7 (individual riser height) inches equals 98
inches.
Then you need to add the total riser and stair tread numbers together.
143 inches plus 98 inches equals 241 inches. This is the linear length
of the stairway, in inches.
In order to find the amount of feet, I need to divide 241 inches by 12.
This provides me with 20.08 feet. Now I can multiply this number by the
width of the stairway, giving me the total square feet of area that I
will need to carpet my stairway.
Since the stairway width is 36 inches, I will multiply 3 feet times 20
feet, giving me 60 square feet of carpeting. Since carpeting is sold by
the square yard, I will need to convert my square feet measurements to
square yard measurements.
I can do this by dividing 9 into 60, giving me a total of 6.66 square
yards. This is an exact number, you will also need to allow a little
extra carpeting for errors, waste or difficult cuts.
Remember, most of the carpeting you will purchase will be sold in 12
foot widths and this could affect your stair carpet calculations and the
amount of carpeting you will need to purchase.
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