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Concrete Column Calculator

Estimate concrete for round or square columns.

Mason ReidFounder and Lead Estimator at MeasureThen

Last updated 2026-08-21

What Is a Concrete Column Calculator?

A concrete column calculator estimates the concrete needed for round or square columns that carry vertical loads for porches, pergolas, and structural posts. You choose the column shape, enter the diameter or width and height, and the number of columns, then get the total volume. It sizes the pour for a single pier or a full row of columns.

How It Works

Round: Volume (ft³) = π × (Diameter ÷ 2 ÷ 12)² × Height. Square: Volume = (Width ÷ 12)² × Height. × Number of Columns.

Example

A 12 in round column 10 ft tall: π × (0.5)² × 10 = 7.85 ft³ ≈ 0.29 cubic yards before waste.

How to Calculate

  1. Choose the column shape, round or square. For a round porch column, pick round.
  2. Enter the diameter in inches for a round column, such as 12 in.
  3. Enter the column height in feet. A 10 ft tall column is common.
  4. The calculator finds the volume: π × (0.5 ft)² × 10 = 7.85 cubic feet, or about 0.29 cubic yards per column.
  5. Multiply by the number of columns and add 5 to 10% waste for form fit, rebar, and spillage before ordering.

Concrete per Column by Size

Column SizeHeightConcrete per Column
8 in round8 ft0.10 cu yd
10 in round10 ft0.20 cu yd
12 in round10 ft0.29 cu yd
12 in square10 ft0.37 cu yd
16 in square12 ft0.79 cu yd

Sources

Frequently Asked Questions

Round or square columns — does it matter?

Round columns use slightly less concrete for the same width, but square forms are easier to build and brace.

Should I add extra to columns?

Yes — 5–10% waste is smart for columns because of form fit, rebar, and spillage.

How many bags for a column?

Divide the column volume in cubic feet by the bag yield: 0.6 ft³ for an 80 lb bag.

Estimate the cost with the Concrete Cost Calculator or browse Concrete Calculators

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Mason ReidFounder and Lead Estimator at MeasureThen

Mason Reid founded MeasureThen after two decades of hands-on work in construction and estimating. Across residential and light commercial projects, he sized concrete pours, framed walls, hung drywall, and priced out roofing, fencing, and deck work — learning the exact math that every job depends on. At MeasureThen he writes the formulas, checks every calculator against real-world assumptions, and makes sure each one is simple enough for a homeowner to trust and a contractor to use. When he is not measuring twice, he is helping projects stay on budget.

Every MeasureThen calculator uses simple, transparent formulas and standard industry assumptions drawn from common construction practice. We show the math behind each result and include worked examples so you can follow along and double-check the numbers. Results are estimates: materials, labor, and pricing vary by region and market, so always confirm important figures with a licensed professional and your local building codes.