Planning underlay and stair pads

Underlay on stairs does two jobs: it makes the runner feel right underfoot, and it takes the abrasion off the nosings where wear concentrates. The required underlay depends on the runner’s backing and the manufacturer’s fitting instructions; there is no fixed lifespan multiplier.

You can buy it as continuous underlay cut to the runner length, or as pre-cut pads — one per 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.

Continuous underlay

Priced by the same linear unit as the runner and cut to the same length. Simple to order, slightly more material, and it runs down the risers as well as over the treads.

Cut pads per tread

One pad per tread, sized to sit slightly narrower than the runner and to wrap over the nosing. The calculator counts one pad per tread automatically, so a 15 step flight shows 15 pads.

Thickness and grade

A denser, thinner underlay performs better on stairs than a thick soft one, which can let the runner move underfoot. Use the underlay price field to compare two grades on total cost.

Questions people ask

Do I need underlay under a stair runner?: Follow the runner manufacturer’s fitting instructions. Ask the installer which underlay, if any, suits its backing, the stair surface and the chosen installation method.
How many stair pads do I need?: One per tread. A 15 step flight needs 15 pads; landings take a separate cut piece.

Related guides

See all stair runner calculator guides