Concrete cylinder volume and weight
The fetched Omni page handles both cylindrical column pours and test cylinders. It first computes cylinder volume, then multiplies by quantity and waste, and finally converts that total volume into weight using the chosen concrete density.
Core formulas from Omni
V = pi x diameter^2 x height / 4
V_total = V x quantity x (1 + waste)
Weight = V_total x concrete density
Source-backed worked example
Omni's column example uses four concrete cylinders, each 20 in in diameter and 9 ft tall. That produces about 0.7272 yd^3 per column and roughly 3.0543 yd^3 in total after adding 5% waste.