The 3–4 inch reveal rule
The strip of bare stair either side of the runner is called the reveal or the margin. Designers almost universally aim for 3–4in (7.5–10cm) each side. Less than 2in looks like a fitting error; more than 6in makes the runner look mean and stringy on a wide staircase.
Runner width = stair width − (2 × reveal)
A 36in staircase with a 4in reveal each side wants a 28in runner — so you would buy the nearest standard size, 27in.
Standard stair runner widths
| Runner width | Metric | Suits stair width | Reveal each side |
|---|---|---|---|
| 24in | 60cm | 30–32in | 3–4in |
| 27in | 70cm | 33–36in | 3–4.5in |
| 30in | 76cm | 36–38in | 3–4in |
| 32in | 80cm | 38–40in | 3–4in |
| 36in | 90cm | 42in+ | 3in+ |
Know your numbers in 30 seconds
Enter your step count, tread depth and riser height — the stair runner calculator gives you the exact length to order, in metres and feet, with waste included.
Open the stair runner calculatorMeasuring stair width correctly
Measure at the narrowest point of the flight, wall to wall. If one side is open with a balustrade, measure to the inside face of the newel post and spindles — not to the outer edge of the tread, because the runner should not run under the spindles.
When to break the rule
- Narrow staircases under 30in: go as wide as you can and accept a 2–3in reveal — a skinny runner on a narrow stair looks worse than a small margin.
- Grand or period staircases: a wider runner with a generous 4–5in reveal reads as more traditional and lets a decorative stair edge show.
- Very worn or patched stair edges: a wider runner hides more, but check the reveal is even on both sides before committing.
- Patterned runners: centre the pattern, not the physical edge — an off-centre repeat is visible from the bottom of the flight.
Does the reveal have to be equal on both sides?
It should look equal, which is not always the same as being equal. Old staircases are rarely square, and a fitter may split the difference over the length of the flight so the runner appears straight even where the wall is not. Ask your fitter to run a string line before stapling.
Custom widths
Any roll carpet can be cut down and bound or whipped on both edges to make a custom-width runner. Expect to pay for binding by the linear metre on each side, typically a modest addition, and add a week or two of lead time. It is the usual route when your staircase falls awkwardly between standard sizes.
Whatever you decide, get the numbers first: the stair runner calculator doubles as a stair runner length calculator, adding nosing wrap, landings, winders, pattern repeat and waste so you order the right length the first time.
Frequently asked questions
What width should a stair runner be?
Most stair runners are 24in, 27in or 32in wide (60cm, 70cm or 80cm). Choose the width that leaves 3–4 inches of bare stair showing on each side of your staircase.
Can a stair runner be too wide?
Yes. If it leaves less than about 2in of stair either side it reads as a full carpet that was cut badly, and it can interfere with the spindles on an open-sided staircase.
What if my staircase is a different width at the top and bottom?
Measure the narrowest step and choose your runner width from that. A good fitter will then align the runner so the reveal appears consistent rather than mathematically identical.
Know your numbers in 30 seconds
Enter your step count, tread depth and riser height — the stair runner calculator gives you the exact length to order, in metres and feet, with waste included.
Find my runner width