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Staircase calculator

Enter the height to climb and the riser you want: PRAXAO finds the whole number of risers, the real riser height, the tread depth from Blondel’s comfort rule, the total run, the slope and the stringer length.

Configuration

Dimensions

Finished floor to finished floor, in centimetres.

cm
cm
Advanced options

Comfortable risers are often about 16–18 cm.

cm

Blondel’s rule: about 63 cm (usually 60–65 cm).

cm

Vertical thickness of the concrete slab under the inner corners of the steps. For the volume only: it is not a structural thickness.

cm

Enter the dimensions to see the drawing.

Calculation results

Fill in the fields to see the result.

Preliminary estimate from the values entered: not a structural validation and not an execution plan. Check the local rules and the manufacturers’ data.

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Results are provided for information. Check tax rates and legal requirements that apply to you.

How to use it

  1. Enter the total height from finished floor to finished floor, in centimetres.
  2. Set the riser height you would like; the calculator rounds to a whole number of risers.
  3. Check the comfort length (about 63 cm) and the stair width.
  4. Read the risers, treads, run, angle and stringer length.

Examples

270 cm to climb, 17.5 cm riser wanted, 90 cm wide

15 risers of 18.00 cm, 14 treads of 27.0 cm, a run of 378.0 cm, a slope of 33.7°, a stringer of 4.65 m and 3.40 m² of tread surface.

Frequently asked questions

What is Blondel’s rule?

It links the riser (R) and the tread (G) for a comfortable stair: 2 × R + G is about 63 cm, usually between 60 and 65 cm.

Does it check the building code?

No. Maximum riser, minimum tread, headroom, handrails, landings and winders depend on the local regulations and the type of building. This is a preliminary layout, not a validation or an execution drawing.

Why does the riser differ from what I asked?

A staircase has a whole number of equal risers. The calculator rounds the count and divides the height exactly, so the real riser is close to your target.

Can I calculate an L-shaped, U-shaped or spiral staircase?

Yes: choose the layout above the fields. L and U stairs split the risers into two flights joined by a landing and give the landing area, the overall length and width and a geometric concrete volume. A helical stair gives the angle between steps, the total turn, the width left beside the central pole and the height of one full turn, a headroom indicator. The drawing is generated from your values; it is an estimate, not a structural design, and the local rules on landings, headroom and handrails still apply.

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