Stair Runner Length CalculatorStair type
Stair runner length calculator for straight stairs
A straight flight is the one staircase where the arithmetic is genuinely simple: every step is identical, the runner travels in one line, and there are no turns to allow for.
Length = steps × (tread + riser), plus nosing allowance, plus waste. That is the whole calculation.
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
Measure three steps, not one
Even on a straight flight, treads vary by a few millimetres. Measure the third, middle and second-from-top step and use the largest value — running short is far worse than a small offcut.
Watch the bottom step
Bullnose and curtail bottom steps are wider and deeper than the rest and often take a separately cut piece. Measure it on its own and add it rather than averaging it into the flight.
Straight stairs suit a single piece
With no turns, a straight flight can usually take one continuous runner, which looks better and installs faster. Only the roll length limits you.
Questions people ask
- What is the formula for a straight stair runner?
- Number of steps × (tread depth + riser height), plus any nosing allowance and waste percentage.
- Do straight stairs need extra length?
- Only for nosing wrap and waste. There are no turns or winders to allow for, so 5 to 10% is usually enough.