Stair type

Stair runner length calculator for L-shaped stairs

An L-shaped stair is two straight flights joined by a quarter landing where the direction changes by 90°. Treat it as three separate measurements added together.

Lower flight + landing + upper flight, then waste on the whole thing.

Your staircase

Start from typical stair sizes where you live

IRC-style stairs: 10 in minimum tread, 7¾ in maximum riser. Runners are usually 27 in or 32 in wide and sold by the linear foot.

Number of stairs

Count every step you will cover.

Tread depth (in)

Front edge to back of the step. Fractions like 10 1/2 work.

Riser height (in)

The vertical face between two treads.

Waste allowance

Custom%

10% is a common starting point; pattern matching and winders need more.

Add a nosing / overhang allowance per step

Needed when the runner wraps around a projecting nose (Hollywood installs and thick pads). Waterfall installs usually don't need it.

Your stair runner length

20 ft 3.1 in

Total runner required for 13 steps, including a 10% waste allowance.

Total runner length in each unit
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

Side elevation of a staircase. The runner travels across each tread and down each riser, so every step consumes tread depth plus riser height of material.

The three parts

Count the risers below the landing and above it separately — they are rarely equal. Measure the landing along the runner's travel, which on a quarter landing means the leg the runner actually crosses.

Handling the 90° turn

Runner cannot fold cleanly through a right angle. Most fitters cut at the landing and butt or seam the two pieces, which means two extra cut ends. Allow a few extra inches at the turn.

A worked L-shaped example

Nine steps below, a 40 in quarter landing, five steps above, 10 in treads and 7.5 in risers: (9 × 17.5) + 40 + (5 × 17.5) = 285 in. With 10% waste, order 313.5 in (26 ft 2 in).

Questions people ask

Do I need one piece or two for an L-shaped stair?: Two is normal — one per flight, joined at the landing. A single piece cannot turn a right angle without bunching.
How do I measure a quarter landing?: Measure along the path the runner takes across the landing, from the nosing of the lower flight to the base of the upper flight.

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