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Stair Runner Calculator
Quick answer: Runner length = steps × (tread depth + riser height), plus any landing. A cap-and-band install adds about twice the nosing projection per step. Runner width = stair width − twice your reveal.
Runner length, width and pad for a straight flight or a stair with a landing — with the length difference between waterfall and cap-and-band installs built in.
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Waterfall vs cap-and-band
The install style changes the length materially, so pick it before you measure.
| Style | How it runs | Length per step |
|---|---|---|
| Waterfall | Flows straight over the nosing and down to the next tread — the runner does not follow the nosing profile | Tread + riser |
| Cap and band (Hollywood) | Wraps tightly around the nosing and tucks under before dropping | Tread + riser + nosing wrap |
Waterfall is faster, uses less material and suits modern and flat-weave runners. Cap-and-band is the traditional method, shows the stair profile crisply, and is the better choice on patterned runners where you want the pattern to stay square to each tread.
Landings and winders
Runner width and reveal
The exposed stair on either side of the runner is the reveal. Traditional practice is 4 inches each side, though anything from 3 to 6 works visually. Subtract twice the reveal from your stair width to get the runner width. On a 36″ stair with a 4″ reveal, that is a 28″ runner — conveniently close to the common 27″ and 30″ stock widths.
Pad
Runner pad is cut narrower than the runner — usually 1 inch less on each side — so it does not show at the edges. It is fitted to the tread only, not wrapped over the nosing, on both install styles. Pad meaningfully extends the life of the runner and makes the stair quieter, and it is the cheapest part of the job.
Ordering
Runner is sold by the linear foot off a roll. Add the waste allowance below to your calculated length — you need extra for pattern matching on figured runners, for the seam at any landing, and simply for getting the first step right. On a patterned runner, allow a full pattern repeat extra per seam.
Frequently asked questions
How do I measure for a stair runner?
Add the tread depth and riser height for one step, multiply by the number of steps, then add any landing depth. For a waterfall install that is the whole calculation; a cap-and-band install adds roughly twice the nosing projection per step.
What is the difference between waterfall and cap-and-band?
Waterfall runs the runner straight over the nosing and down to the next tread, so it uses less material and installs faster. Cap-and-band wraps the runner tightly around the nosing and tucks it underneath, which shows the stair profile crisply and suits patterned runners.
How wide should a stair runner be?
Subtract twice your chosen reveal from the stair width. With the traditional 4 in reveal on each side of a 36 in stair, the runner is 28 in — close to the common 27 in and 30 in stock widths.
Do I need padding under a stair runner?
It is strongly worth it. Pad extends runner life considerably, makes the stair quieter and softer underfoot, and is the cheapest component of the job. Cut it about 1 inch narrower than the runner on each side so it does not show at the edges.