About this calculator

This site exists to answer one question well: how much runner do my stairs need? You enter your tread depth, riser height and step count, and it works out a length in inches, feet, yards and metres, with landings, nosing wrap, waste and fitting allowance added if you want them.

How the numbers are worked out

Each covered step adds its tread depth plus its riser height. Landings, any extra wrap around the nose of each step and winder allowances are added next. Waste is applied as a percentage of that total, then a fixed fitting allowance, then the figure is rounded up to the purchase length you choose. Everything is calculated in inches at full precision and only rounded when shown.

The formulas are covered by automated tests, including unequal steps, metric input and rejection of impossible values. You can see every step of a result in the breakdown under the estimate.

What it cannot do

• It does not draw a cutting plan for winders, curved or spiral stairs.
• It does not allow for pattern repeat or decide where joins should go.
• It does not model the shape of bullnose or curtail bottom steps.

Treat the result as a well-checked estimate. Your fitter or supplier should confirm the final order, especially for patterned runners and stairs that turn.

Your data

Calculations run in your browser and you do not need an account. See the privacy policy for details.