Concrete Column Calculator

What is a Concrete Column?

A concrete column (often referred to as a pier when used in foundational work) is a vertical structural element designed primarily to carry compressive loads. They are universally used in construction to support beams, arches, floors, and roofs. Whether you are pouring footings for a backyard deck, creating supports for a massive commercial structure, or erecting decorative pillars, concrete columns provide unmatched durability and load-bearing capacity.

Because concrete columns are cylindrical, calculating their volume requires a slightly different mathematical approach than a standard rectangular slab or footing. You must find the area of the circular face and multiply it by the height of the column.

How to Calculate Concrete Volume for a Column

Concrete is sold by volume, specifically the cubic yard. To determine how much concrete to order for a cylindrical column or pier, you need to calculate the volume of a cylinder.

The Formula

To find the volume of a cylinder in cubic yards:

1. Divide the Diameter (in inches) by 2 to find the Radius.
2. Convert the Radius to feet by dividing it by 12.
3. Square the radius (multiply it by itself).
4. Multiply the squared radius by Pi (π ≈ 3.14159) to get the area of the circular face in square feet.
5. Multiply that area by the Height (ft) to get the total Cubic Feet.
6. Divide the total cubic feet by 27 to convert to Cubic Yards.

Example Calculation

Imagine you are pouring a concrete pier for a deck. The pier needs to be 18 inches in diameter and 4 feet deep.

1. Find Radius in feet: 18 ÷ 2 = 9 inches. Then 9 ÷ 12 = 0.75 ft.
2. Square the Radius: 0.75 × 0.75 = 0.5625.
3. Find Area: 3.14159 × 0.5625 ≈ 1.767 square feet.
4. Find Cubic Feet: 1.767 sq ft × 4 ft = 7.068 cubic feet.
5. Find Cubic Yards: 7.068 ÷ 27 ≈ 0.26 cubic yards.

(Note: 0.26 cubic yards is small enough that you might consider mixing bagged concrete rather than ordering a delivery truck, which often has minimum load fees.)

Forming Concrete Columns

Pouring a perfectly cylindrical column requires specialized forms. The most common method in residential and light commercial construction is using heavy-duty cardboard forming tubes (often referred to by the brand name Sonotube). These are placed into the excavated hole or set above ground, braced securely, and then filled with concrete. Once the concrete cures, the cardboard is simply peeled away, leaving a smooth, perfect cylinder.