Planning a runner for curved stairs

On a curved staircase the outside of every tread travels further than the inside, so a straight-flight formula will always under-read.

Measure along the runner's intended centre line and use that as your tread depth. The result is an estimate for budgeting, not a cutting list.

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.

Measuring along the centre line

Chalk the line the runner will follow, then measure each tread's depth on that line. The difference depends on the curve and the runner’s width. Record each tread rather than assuming one dimension applies to the whole flight.

Why curved runners are templated

The runner has to be cut on a curve to stay centred, which means the piece is not rectangular. Suppliers who make curved runners work from a cardboard or digital template of every tread.

Budget allowance

Ask the installer for a cutting allowance and labour quote for the actual curve. The estimate here is best used to sanity-check a quote rather than to place an order.

Questions people ask

Can I use a standard calculator for curved stairs?: Only for a preliminary budget. Have the actual runner path, cut shapes and fitting allowance checked on site before ordering.
Why is a curved stair runner more expensive?: Each tread is cut individually on a curve, edges need binding, and offcuts cannot be reused — material waste and labour are both higher.

Related guides

See all stair runner calculator guides