Stair Runner Length CalculatorStair type
Stair runner length calculator for curved stairs
On a curved staircase the outside of every tread travels further than the inside, so a straight-flight formula will always under-read.
Measure along the runner's intended centre line and use that as your tread depth. The result is an estimate for budgeting, not a cutting list.
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
Measuring along the centre line
Chalk the line the runner will follow, then measure each tread's depth on that line. On a gentle radius the difference from a straight tread is small; on a tight curve it can be 30% more.
Why curved runners are templated
The runner has to be cut on a curve to stay centred, which means the piece is not rectangular. Suppliers who make curved runners work from a cardboard or digital template of every tread.
Budget allowance
Add 20 to 25% waste on a curved flight, and expect a higher labour rate. The estimate here is best used to sanity-check a quote rather than to place an order.
Questions people ask
- Can I use a standard calculator for curved stairs?
- Only for a rough budget. Measure along the runner's centre line and add 20 to 25% waste, then have the treads templated before ordering.
- Why is a curved stair runner more expensive?
- Each tread is cut individually on a curve, edges need binding, and offcuts cannot be reused — material waste and labour are both higher.