What you need
- A retractable tape measure (a flexible dressmaker's tape helps on wrapped nosings)
- A notepad or your phone
- Ten minutes and an empty staircase
The four measurements that matter
- Number of steps — count treads, not risers. Walk up and count each surface you stand on.
- Tread depth — front edge of the step to the face of the riser behind it, measured on a middle step.
- Riser height — the vertical face from the back of one tread up to the front of the next.
- Stair width — wall to wall, or wall to the inside face of the balusters, measured at the narrowest step.
Measure three steps, not one
Older staircases are rarely uniform. Measure the bottom, middle and top step and use the largest tread and riser figures — ordering to the smallest measurement is how people end up short.
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 the nosing
The nosing is the lip that overhangs the riser. Hook your tape under the overhang and measure from the front edge of the tread back to the riser face — usually 0.75in to 1.5in. You only need this number if you are wrapping the nosing rather than fitting waterfall style, but note it anyway; suppliers ask.
Measuring landings
Measure the straight-line path the runner will take across the landing, in the direction of travel. On a quarter-turn landing that path is an L, so measure both legs and add them. Add 4–6in per landing for the fitter to square and joint the piece.
Measuring winder and pie steps
Winders taper from a narrow inside edge to a wide outside edge. Always measure the widest point of the tread, because the runner has to be cut to cover it. Record each winder separately — on a three-step winder turn the widest points are often quite different.
Common mistakes
| Mistake | What it costs you |
|---|---|
| Counting risers instead of treads | One extra or one missing step |
| Measuring one step and multiplying | Up to 15cm of error on an older staircase |
| Forgetting the nosing wrap | Almost a full metre on 13 steps |
| No waste margin | No room for trimming or repairs |
| Ignoring the pattern repeat | Mismatched pattern at every flight change |
Turning measurements into an order
Once you have your four numbers, feed them into the stair runner calculator. It applies the tread-plus-riser formula per step, adds nosing, landings, winders and pattern allowance, applies your waste margin and rounds up to a sensible purchase length in metres, feet and yards.
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 do you measure stairs for a runner?
Count the treads, then measure tread depth, riser height and stair width on a middle step. Multiply tread plus riser by the number of steps, add allowances for nosing wrap, landings and pattern repeat, then add 10% waste.
Should I measure before or after choosing a runner?
Measure first. Your stair width determines which runner widths will look right, and your step count determines whether a pattern repeat is affordable. Both narrow the shortlist before you fall in love with something that will not fit.
Can a fitter measure for me?
Most fitters will measure as part of a quote, and many carpet retailers offer a free measuring service. Doing your own measurements first still helps — it lets you sanity-check the quote and budget before anyone visits.
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.
Turn my measurements into a length