Measuring a carpet stair runner

Carpet runners come two ways: cut from broadloom and bound to your width, or bought ready-made in a fixed width. The length calculation is the same, but the buying constraints are not.

Cut-from-broadloom gives you any width you like; ready-made limits you to what the maker offers.

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.

Pile direction matters

Carpet pile should run down the stairs, so the runner is cut along the roll length, not across it. That is why the roll length, not the roll width, limits how long a single piece can be.

Pattern repeat and waste

Decide with the installer how the pattern should line up. Ask the supplier for the repeat dimensions and a cutting plan; a waste percentage does not automatically align repeats on each tread.

Binding and serging

Cut broadloom needs both long edges finished. Cotton or linen binding is the usual choice; serging is more expensive and gives a hand-finished edge. Both are priced per linear foot or metre of edge — that is twice your runner length.

Questions people ask

How much carpet do I need for a stair runner?: Steps × (tread + riser), plus nosing allowance and 10% waste. A 14 step flight typically needs about 22 ft 6 in of carpet.
Do I pay for binding by the length?: Usually yes, and it applies to both long edges — so budget roughly twice the runner length in binding.

Related guides

See all stair runner calculator guides