Stairs Carpet Calculator . Use our advanced calculator to determine the cost of carpet installation. Calculate how much carpet you need to install flooring and estimate the carpet installation cost. Victorian stair clip in antique brass for a traditional ... (Bill Kelly) This free stair calculator determines stair parameters such as rise, total run, and angle, stringer length, based on height, run, tread, and headroom requirement. 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. Luckily, our stairs carpet calculator takes the guesswork out. For stairs, measure one stair tread from one side to the other side of the rail (or wall) and then round it off to the nearest foot. Carpet Calculator is a simple application that lets you calculate the cost of carpeting a room. The Best ...