Choosing runner width and length

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.

Your staircase

Optional starting measurements

Example measurements only, not building-code advice. Replace them with measurements from your own stairs.

Check a few steps before using one set of measurements for the whole flight.

Number of stairs

Count the tread-and-riser pairs the runner will cover. Exclude landings.

Tread depth (in)

Measure the runner path across the flat tread. Fractions like 10 1/2 work.

Riser height (in)

The vertical face between two treads.

Waste allowance

Custom%

10% is the starting allowance here, not a guarantee. Ask your fitter about patterns and turns.

Add a nosing / overhang allowance per step

Enter the extra runner path around the edge, including any underside wrap. Do not add it twice if it is already included in your measurements.

Your runner estimate

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

Length to order

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.

One step, shown in profile

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 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. This is a visual starting point, not a safety rule. A narrower or wider reveal can suit the staircase; check clearance and the finished width before ordering.

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.

Related guides

See all stair runner calculator guides