Concrete Stairs Volume Calculator

Work out concrete stairs volume instantly with clear inputs, formula shown and shareable results.

About Concrete Stairs Volume Calculator

A concrete flight is two volumes added together: the triangular steps, each half the riser times the tread times the width, and the inclined waist slab beneath them, taken here as 150 mm thick along the sloping length. The sloping length per step is the hypotenuse of the riser and tread.

Formulas

Step volume

V = 0.5 x riser x tread x number of risers x width

Waist volume

V = number of risers x sqrt(riser² + tread²) x waist thickness x width

Worked example

With the default values below, Concrete Stairs Volume Calculator returns Total concrete volume of 1.244. Change any input above and every figure here is recalculated in your browser.

Inputs used

Number of risersminimum 1: 14
Riser heightminimum 0.05 m: 0.175 m
Tread depthminimum 0.1 m: 0.28 m
Stair widthminimum 0.5 m: 1.2 m

Results

Total concrete volume: 1.244 m³
Volume of the steps: 0.4116 m³
Volume of the waist slab: 0.8321 m³
Total rise: 2.450 m

Step by step

1Values used
2Step volume
3Waist volume
4Total concrete volume= 1.244 m³
5Volume of the steps= 0.4116 m³
6Volume of the waist slab= 0.8321 m³
7Total rise= 2.450 m

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Preliminary estimate only. Stair geometry, waist thickness and reinforcement must be verified by a qualified engineer against local building code.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Stair geometry, waist thickness and reinforcement must be verified by a qualified engineer against local building code.

Frequently Asked Questions

How is the Concrete Stairs Volume figure worked out?

V = 0.5 x riser x tread x number of risers x width. A concrete flight is two volumes added together: the triangular steps, each half the riser times the tread times the width, and the inclined waist slab beneath them, taken here as 150 mm thick along the sloping length.

What riser and tread should I use?

A comfortable flight satisfies 2 x riser + tread of about 600-640 mm. Most codes cap the riser near 190 mm and require a tread of at least 250 mm.

What values do I need to enter?

This calculator takes 4 inputs: Number of risers, Riser height, Tread depth, Stair width. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.