Measuring treads and risers

Tread depth and riser height are the two measurements that decide everything. Get them right and the rest of the calculation is arithmetic.

Tread depth is the horizontal surface you walk on, measured from the face of one riser to the front edge of the nosing. Riser height is the vertical face between two treads.

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 the tread

Record the full tread depth, including the front edge. Ask the installer what extra wrap remains beyond that measurement so the same overhang is not counted twice. Measure at the centre of the step, and check three separate steps — older stairs are rarely uniform.

Measuring the riser

Measure from the top of one tread to the top of the next, at the front. On carpeted stairs, measure to the timber, not to the existing carpet surface.

When the steps are not equal

Use the largest tread and largest riser you find rather than an average. Being half an inch long on every step costs you a few inches of offcut; being half an inch short costs you the whole runner.

Questions people ask

Should tread depth include the nosing?: Measure the tread to its front edge. Any extra allowance should cover the additional fitted path only; do not count an overhang twice if it is already included in your tread measurement.
What if my steps are different sizes?: Choose Measure each step and enter each straight step’s tread depth and riser height. Have a bullnose or curtail bottom step measured separately; entering its dimensions does not model its individual cut shape.

Related guides

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