The stair runner length formula
For a straight flight, the runner has to travel across the flat part of each step and down the vertical face below it. That means:
Runner length = steps × (tread depth + riser height), + nosing, + landings, + waste
Tread is the horizontal surface you stand on. Riser is the vertical face between two treads. Nosing is the lip that overhangs the riser — it only adds length if you wrap it.
Everything else in a stair runner calculation is an adjustment on top of that core number: pattern matching, winder steps, landings, and a waste margin so the fitter has something to trim.
Worked example: 13 steps
Take the most common staircase in a US or UK home — 13 steps, a 10in tread and a 7.5in riser, fitted waterfall style with no nosing wrap.
| Element | Maths | Length |
|---|---|---|
| Treads | 13 × 10in | 130in |
| Risers | 13 × 7.5in | 97.5in |
| Subtotal | — | 227.5in (5.78m) |
| Waste at 10% | 227.5 × 0.10 | 22.75in |
| Total to order | — | 250.25in ≈ 6.36m / 20ft 10in |
Round that up to the next half metre and you would buy 6.5m. If the runner comes on a roll sold by the linear yard, that is 7 yards.
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 calculatorAdjusting for a wrapped (Hollywood) installation
A waterfall installation lets the runner fall straight from the nosing to the next tread, so the nosing adds nothing. A wrapped or Hollywood installation pulls the runner tight around the curve of the nosing, following the profile of the step. That adds roughly twice the nosing depth per step.
With a 1.25in nosing on 13 steps that is an extra 32.5in — nearly a metre. It is the single most common reason a runner order comes up short.
Adding landings
A landing is measured as a simple flat run: the length the runner travels across it, front edge to back edge. Add each landing's length once. If the runner turns on the landing, measure the longest path the runner takes, then add a little extra so the fitter can square the joint.
Adding winder steps
Winder (pie-shaped) steps are always measured at their widest point, because the runner has to be cut to cover the deepest part of the tread. A winder with a 24in widest tread and a 7.5in riser eats 31.5in of runner — three times a regular step. Count winders separately from your straight steps rather than averaging them in.
Pattern repeat allowance
If the runner carries a pattern, the fitter needs freedom to start each flight at the same point in the repeat. The safe rule is to add one full pattern repeat per flight and per landing. On a large-repeat herringbone or a bold stripe that can add 10–15% to the order.
How much waste to allow
| Staircase | Suggested waste margin |
|---|---|
| Straight flight, plain runner | 5–10% |
| Straight flight, patterned runner | 10–15% |
| L-shaped with one landing | 10–15% |
| U-shaped or winders | 15–20% |
Waste is not wasted money. Off-cuts are what a fitter uses to correct a mis-measured step, and a leftover metre is a cheap insurance policy against a dye-lot that no longer matches in two years.
Metres, feet or yards?
Most runners are sold by the linear metre in the UK and Europe and by the linear foot or yard in the US. Convert once at the end, never mid-calculation: 1m = 39.37in, 1ft = 12in, 1yd = 36in. The calculator on this site shows every result in all three so you can order from any supplier.
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
How much stair runner do I need for 13 steps?
For 13 standard steps with a 10in tread and 7.5in riser, allow about 5.8m (19ft) of runner before waste, and roughly 6.4m (21ft) once you add a 10% margin. Wrapping the nosings or adding a landing pushes that higher.
Do I include the top step in my measurement?
Count every tread the runner will cover. The top step is often a landing edge rather than a full step, so check whether the runner finishes at the nosing of the top tread or carries onto the landing floor — the two differ by up to a full step's worth of material.
Should I measure in inches or centimetres?
Use whichever unit your supplier prices in, and stick to it for every measurement. Mixing units mid-calculation is the most common source of ordering errors.
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.
Calculate my runner length