Work out concrete stairs volume instantly with clear inputs, formula shown and shareable results.
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.
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
Preliminary estimate only. Stair geometry, waist thickness and reinforcement must be verified by a qualified engineer against local building code.
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.
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.
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.