Stair Runner Length CalculatorStep count
Stair runner length calculator by step count
If you only know how many steps you have, this is the fastest route to a usable number. The table below assumes a 10 in tread and a 7.5 in riser — 17.5 in of runner per step — and no waste.
Change either dimension in the calculator to get the figure for your own staircase.
Stair runner calculator
Your stair runner length
20 ft 3.1 in
Total runner required for 13 steps, including a 10% waste allowance.
| Inches | 243.1 in |
|---|---|
| Feet | 20.26 ft |
| Feet & inches | 20 ft 3.1 in |
| Yards | 6.75 yd |
| Meters | 6.17 m |
| Centimeters | 617.47 cm |
Recommended purchase length
21 ft
7 yd · 6.4 m · 252 in
This calculator provides an estimate based on the measurements and installation assumptions you enter. Complex, curved or winder staircases may require professional measurement.
Your measurements, drawn to scale
Runner length by number of stairs
8 steps: 140 in (11 ft 8 in). 10 steps: 175 in (14 ft 7 in). 12 steps: 210 in (17 ft 6 in). 13 steps: 227.5 in (18 ft 11.5 in). 14 steps: 245 in (20 ft 5 in). 15 steps: 262.5 in (21 ft 10.5 in). 16 steps: 280 in (23 ft 4 in). 18 steps: 315 in (26 ft 3 in). 20 steps: 350 in (29 ft 2 in).
Add your allowances
Every figure above is bare length. Add 10% for waste and the depth of any landing before ordering.
Count risers, not treads
The number that matters is how many vertical faces the runner covers. On most flights that is one more than the number of full treads.
Questions people ask
- How much runner per step?
- About 17.5 in on a standard US stair (10 in tread + 7.5 in riser) or about 41.5 cm on a typical UK stair.
- Is the step count the same as the riser count?
- For runner purposes, count risers. Each riser plus its tread is one unit of runner length.