Concrete Cylinder Calculator

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Construction

Calculate the volume of concrete needed to fill a cylindrical form such as a column, sonotube, or post hole.

Formula

Volume = π × r² × h × quantity ÷ 1728
  • r = radius = diameter ÷ 2; all dimensions in inches, result in cu ft.
  • Add 5–10% for waste.

12 in diameter, 48 in deep, 1 column

Inputs
  • Diameter: 12 in
  • Depth / Height: 48 in
  • Number of Cylinders: 1

π × 36 × 48 / 1728 = 5,429 / 1728 ≈ 3.14 cu ft → 6 bags.

Frequently asked questions

What diameter sonotube do I need?
Depends on post size and load. A 4×4 post typically uses an 8-12 in tube; 6×6 post uses 12-16 in.