Formula
The area of the circle uses the diameter in inches. Dividing by 3,888 also converts cubic feet to cubic yards:
cubic yards = count × π × (diameter / 2)² × height / 3888
Height is feet. A square pier is not this shape; measure that as a rectangular pour on the concrete page.
Assumptions
- Every column has the same diameter and height.
- The section is a circle.
- No capitals or pads are included.
Worked example
Four columns, 12 inches across and 10 feet tall, are 1.16 yd³.
Input definitions
- Diameter
- The full width of the round section, in inches.
- Height
- The pour height in feet.
Limitations
This is a planning quantity. It is not a structural design, a permit drawing, or a supplier's guaranteed yield.
Questions
Why divide by 3,888?
The radius is squared in inches, so 144 makes it square feet, and 27 makes the height into cubic yards. 144 times 27 is 3,888.
Can I enter a square column?
No. Use the concrete calculator and enter the square side as length and width.