How the calculation works
The formulas
Add separate elements, choose each shape, and enter its dimensions and count. Cylinder height is axial length. The allowance increases the net geometric volume; an optional price applies per cubic metre.
Rectangular volume = length × width × height × count
Cylinder volume = π × diameter² ÷ 4 × height × count
Order volume = Σ(volumes) × (1 + allowance/100)
Assumptions to check
- Elements must not overlap; shared volumes are not automatically deducted.
- This is quantity arithmetic, not mix specification, structural design, or formwork design.
A worked example
A 5 × 4 m slab, 100 mm thick, has a net volume of 2 m³. A 5% allowance gives 2.1 m³ to order.