Stair Runner Length CalculatorSizing
Stair runner width and length calculator
Length decides how much you buy; width decides how it looks. Get the width wrong and no amount of correct length will save the job.
Enter your stair width and your intended runner width and the calculator returns the reveal — the strip of bare stair showing on each side — and tells you whether it sits in the range designers aim for.
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
The reveal formula
Reveal per side = (stair width − runner width) ÷ 2. A 36 in stair with a 27 in runner leaves 4.5 in each side. A 90 cm stair with a 70 cm runner leaves 10 cm each side.
What counts as a good reveal
Roughly 3 to 5 in (7 to 13 cm) per side reads as balanced. Under 2 in looks like a failed wall-to-wall carpet; over 6 in can look mean unless the stair is unusually wide.
Measure the narrowest point
Stairs are rarely parallel. Measure at the bottom, middle and top and size the runner to the narrowest measurement, or it will foul the string somewhere up the flight.
Questions people ask
- What width stair runner should I choose?
- Pick a width that leaves 3 to 5 in (7 to 13 cm) of bare stair on each side. On a 36 in stair that means a 27 or 30 in runner.
- Does runner width change the length I need?
- No — length depends on treads and risers. Width affects cost per foot, rod length and the look.