To calculate the length of the staircase for a runner you need to.
Measure pie stairwell carpet.
Stair runners usually sold by the running foot or yard can be 22 to 36 inches wide.
Do this for 2 3 stairs in case there are any variations in width.
This number tells you how wide the carpet needs to be to cover the stairs.
Use the tape measure to obtain the fall of each step.
The important thing is to measure each individual stair separately.
How to measure for carpet stair runners.
Some weaves expose carpet backing when bent and thus are not suitable for stairs.
How to measure stairs and landing for carpet.
There are individual parts a landing a hall and the stairs part which may be a combination of straight stairs and winding stairs.
Add on no matter how much carpet you calculate you need you should always buy just a bit extra to allow for any oddities or mistakes when installing it.
Bend carpet samples in half before making your purchase.
Three pieces each 48 x 30 for a total of 4320 square inches.
For a curved staircase that is open on one side and contains 12 cap pie stairs without a bullnose stair you would need 12 x 10 of carpet.
Bear in mind that some geometric patterned carpet may be hard to match on pie shaped stairs.
Position the tape measure at the edge of the rise and pull it down to the bottom of the fall of the stair where it adjoins the step below it lol.
At a minimum matching patterns may result in excess waste.
Stretch out the measuring tape parallel to the edge of a stair to get the width.
12 stairs each 48 wide with a rise of 8 and a tread of 10 plus 3 for the nose.
This is a little trickier perhaps but follows the same principle as measuring a room.
The total is 12 096 square inches.
The stairs take a 90 degree turn at a corner so three of the stairs are pie stairs.