How is step volume calculated?
Each step is treated as a triangular prism: half of riser × tread × stair width.
Stair Concrete Calculator
Calculate concrete volume for cast-in-place stairs including steps, optional landing, and wastage.
Stair Concrete Calculator Formula
- Step Volume
(Riser × Tread ÷ 2) × Width per step - Steps Total
Volume per step × Number of steps - Landing Volume
Landing Length × Width × Thickness (if provided) - Wastage Allowance
(Steps + Landing) × (1 + Wastage ÷ 100)
Assumptions
- Each step is modelled as a triangular wedge (solid concrete stair profile).
- Waist slab and stringer beams are excluded unless included in landing dimensions.
- Landing fields are optional; leave at zero when not applicable.
Frequently Asked Questions
Do I need to enter landing dimensions?
Only if the flight includes a mid-landing or top landing pad. Leave landing fields at zero otherwise.
What wastage is typical for stairs?
10–15% is common because of complex formwork and finishing waste.