Concrete Column Calculator
Column concrete is the cross-section area × concrete height × number of columns: π × (diameter ÷ 2)² for round, side² for square, width × breadth for rectangular. Four 12 in round columns 9 ft high need 28.27 ft³ (1.05 yd³), or 1.16 yd³ with 10% waste. Pour the footing separately with the Concrete Footing Calculator.
How it's calculated: Volume = cross-section area (round, square or rectangular) × concrete height × number of columns.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Round: V = π × (Diameter ÷ 2)² × Height × count
Square: V = Side² × Height × count
Rectangular: V = Width × Breadth × Height × count
Run the calculation to see each step with your own numbers.
Four round columns, 12 in diameter, 9 ft high, 10% waste.
Per column = π × 0.5² × 9 = 7.07 ft³
Total = 28.27 ft³ = 1.05 yd³ exact
+10%: order 1.16 yd³
- Straight prismatic column of constant cross-section — no capital, base flare or haunch.
- Height is the concrete height, not the form length.
- A separate footing/pad below the column is not included.
- Round or square — does it matter much?
- Yes. A 12 in square column holds about 27% more concrete than a 12 in round one (π/4 ≈ 0.785 of the square).
- Is the footing under the column included?
- No. This is the column concrete only. Size and pour the footing or pad below it separately with the Concrete Footing Calculator.
- What height do I enter?
- The height of concrete in the column — top of footing to top of column, or floor to underside of the beam it supports. If your forms run long, enter how far up you will fill them, not the form length.
- How much concrete is in a 12 inch round column?
- About 0.785 ft³ per foot of height (π × 0.5² ft²). A 9 ft column holds 7.07 ft³, so four of them take 28.27 ft³ — 1.05 yd³ exact, or 1.16 yd³ with the default 10% waste.
- How do you calculate concrete for a square column?
- Multiply the side length by itself, then by the concrete height and the number of columns. A 12 in square column holds 1 ft³ per foot of height — about 27% more than a 12 in round column.
Geometry
Standard geometry — cylinder and prism volume. Unit conversions per NIST SP 811.
About the Concrete Column Calculator
The Concrete Column Calculator gives the concrete volume for a set of freestanding columns — round, square or rectangular — from the cross-section size, the column height and how many you are pouring. Use it for above-ground columns and posts; for a drilled or formed foundation below grade use the Concrete Pier Calculator, and for round cardboard tube forms the Sonotube Concrete Calculator. Enter the height of concrete, not the full form length, and pour the footing beneath as a separate calculation.
What you enter
- Column shape
- Diameter
- Width / side
- Width
- Breadth
- Column height
- Number of columns
- Waste allowance — Default 10%. Adjust to your own allowance — the exact figure is always shown too.
What you get back
- Concrete volume — shown as the exact figure and, separately, a recommended figure with your waste allowance added.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Concrete Calculator — How much concrete a rectangular slab or footing needs, in cubic yards or cubic metres.
- Sonotube Concrete Calculator — Concrete volume for round column forms (Sonotube-style tubes).
- Concrete Pier Calculator — Concrete volume for pier foundations with an optional bell base.
- Concrete Footing Calculator — Concrete volume for strip and pad footings.
Related articles
- Exact Quantity vs Recommended Order Quantity — Every BuildNumerics calculator shows two figures on purpose — the exact geometric answer, and a separate, waste-adjusted number you can actually order.
Part of the Concrete calculators.