Planning carpet for open-riser stairs

With open risers there is nothing behind the tread, so the runner covers the tread and wraps around the front and often underneath the nosing — but it does not run down a riser face.

For tread-only coverings, use a separate measured piece plan. The standard calculator models covered treads and risers, not open gaps or the underside of each tread.

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.

Treads-only calculation

Length = steps × (tread depth + wrap). A typical wrap is 2 to 3 in to take the runner over the nosing and under the tread edge where it is stapled out of sight.

Cut pads are often better

On open risers, individual bound tread pads look cleaner than a continuous runner, because a continuous piece has nothing to sit against between treads. Count one pad per tread in the materials list.

Fixing without risers

Without a riser face, the usual rod-and-bracket layout may not suit the stair. Ask the installer for a secure fixing method approved for the carpet and tread surface.

Questions people ask

Do open riser stairs need less runner?: Tread-only pieces may use less length, but wraps, backing, cutting shapes and edge finishing affect the order. Measure each piece rather than subtracting a fixed percentage.
Can I use stair rods on open risers?: Usually not — there is no riser face to fix brackets into. Adhesive, tape or concealed staples are the normal alternatives.

Related guides

See all stair runner calculator guides