A stair runner is a strip of carpet that runs down the middle of a staircase, leaving the wood visible at the sides. Because it wraps every tread, riser and nosing, it takes more length than people expect. This calculator adds it up.
The length per step
Each step uses:
- the tread depth, the flat part you step on;
- the riser height, the vertical part;
- the nosing wrap, the extra the runner needs to bend around the front edge, about 1 in depending on the shape and the padding.
length = steps × (tread + riser + nosing wrap) + landing, then add a margin.
Example
Thirteen steps with 10 in treads, 7.5 in risers and a 1 in nosing wrap take 13 × 18.5 = 240.5 in. With 12 in at the ends and 5% extra for trimming and pattern matching:
(240.5 + 12) × 1.05 = 265 in, about 22.1 ft. Buy 23 ft.
Width
Common runner widths are 27 in and 32 in, leaving 3 to 6 in of wood showing on each side. Measure the stair width and center the runner; on narrow stairs a 22 to 24 in runner looks better.
Installation style
- Waterfall: the runner falls straight from the nosing to the bottom of the riser. It is the simplest and uses the least material.
- Hollywood (upholstered): the runner is tucked tightly under each nosing and stapled along the riser. It looks tailored and uses the nosing wrap allowance.
Turns and landings
Winder steps and turns need extra length and often separate pieces cut to shape. Measure a landing as its depth plus any length you want to carry onto the floor above or below, and enter it in the landing field.
Rods, padding and fixing
- Stair rods are decorative bars at the base of each riser, one per step. Today the runner is held by staples or tack strips, and the rods are optional.
- Use a thin, firm pad cut 1 to 2 in narrower than the runner.
- Patterned runners need extra so the pattern repeats on each step; increase the margin.
Cost
Runner by the linear foot ranges from about $20 for basic flatweaves to over $100 for wool. Professional installation is usually priced per step.