How much carpet do I need for 13 or 14 steps?

Measure one tread depth plus one riser height, add a small allowance for the nosing wrap and the tuck at the back of the tread, then multiply by the stair width. Multiply that per-step area by the number of steps, add any landing areas, and apply a 10 percent waste factor for plain carpet or 15 to 20 percent for patterned carpet. Finally, divide square feet by 9 to get the square-yard order quantity, since carpet is sold by the square yard.

What is the difference between waterfall and Hollywood carpet installation on stairs?

In a waterfall installation, the carpet falls straight from the edge of one tread down to the next, leaving the riser face smooth. In a Hollywood, or upholstered, installation, the carpet wraps around the nosing and is tucked under it, giving each step a tailored, wrapped look. Hollywood uses more carpet per step because of the wrap, and it shows off the carpet texture more clearly, while waterfall is simpler and uses slightly less material.

What waste factor should I use for patterned stair carpet?

Use 15 to 20 percent for patterned, striped, or directional carpet, compared with 10 percent for plain solid-color carpet. Every tread and riser has to be cut so the pattern aligns from one step to the next, and that matching consumes extra material on each step. The bolder and larger the pattern repeat, the closer to the 20 percent end of the range you should plan for.

Can I install carpet over existing stair treads?

Usually yes, as long as the existing treads are solid, level, and securely fastened. Remove any old carpeting, staples, and tack strips first, and check that the nosing edges are smooth and slightly rounded so the new carpet does not wear through prematurely. Keep in mind that carpet plus padding raises each tread slightly, which makes the bottom riser a little shorter and the top riser a little taller, so factor the added thickness into your measurements.

What type of carpet is best for stairs?

A low-pile, densely constructed carpet wears best on stairs, which get more concentrated foot traffic than a flat room. Dense construction resists matting and shows less wear on the nosing, which is the highest-abuse point of every step. Avoid very thick plush carpets, since they are harder to wrap tightly around nosings and tend to look worn on stair edges much sooner.

Do stairs need carpet padding, and what kind?

Yes, stairs benefit from padding, which improves comfort underfoot and helps the carpet last longer by absorbing impact. Use a dense pad made for stairs, typically thinner than the pads used in rooms so the carpet can still wrap cleanly around the nosing and tuck into the crotch without bunching. A pad that is too soft or too thick will make the tread feel spongy and wear faster at the nosing.

How do I convert my stair measurement from square feet to square yards for a carpet order?

Divide the total square feet by 9. Carpet is sold by the square yard, which equals 9 square feet, so the same measurement is a much smaller number in yards than in feet. Always apply your waste factor before converting, so the waste is included in the final yardage you order.

Carpet/Flooring Calculator

What Is the Carpet/Flooring Calculator?

Estimating flooring material for a staircase is one of the trickiest measuring jobs in a home project, because stairs are not flat floors. Every step wraps carpet around the nosing and tucks it into the crotch where the tread meets the riser, so a flat-area calculation based on tread and riser dimensions alone will come up short. The unit of sale also changes with the material: broadloom carpet is sold by the square yard (9 square feet), while luxury vinyl, tile, and hardwood are sold by the square foot or by the carton, so converting units before you order is essential. Installation style changes the math too. A waterfall installation lets the carpet fall straight down the riser, while a Hollywood, or upholstered, installation wraps the carpet around the tread and tucks it under the nosing, which uses more material on every step. Patterned carpet adds another layer of waste: each tread and riser has to be cut so the pattern lines up from one step to the next, and that matching can push cutting waste from 10 percent up to 15 or 20 percent. Landings and pie-shaped treads on turning stairs add area that must be measured separately. This calculator works through the tread-plus-riser measurement for every step, adds landing areas, applies an adjustable waste factor, and converts the result into square feet, square yards, and the order quantity you hand to the supplier.

How to Use This Calculator

Measure the tread depth and the riser height of one representative step, both in inches. Measure from finished surface to finished surface, since a thick existing floor covering changes the numbers.
Measure the stair width, also in inches. If the width varies between the treads, measure the widest step and use that figure.
Enter the number of steps in the flight. Count risers carefully: a 14-riser stair has 14 risers but only 13 treads if the landing counts as the last tread.
Choose the installation style: waterfall, where the carpet falls straight down the riser, or Hollywood/upholstered, where the carpet wraps around the nosing and tucks under it, which needs more material per step.

Carpet/Flooring Calculator

Carpet / Flooring Calculator

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