Concrete Column Calculator
By Vinod Kondeti · Updated
Round columns and piers are cylinders: π × radius² × height. Enter the diameter in inches. The calculator halves it and converts it to feet, so you do not mix up radius and diameter.
How do I measure for a column pour?
- Use the inside diameter of the form tube.
- For a square column, use the wall calculator with length = width = the side of the column.
- Enter the number of identical columns as the quantity.
Column concrete questions
How much concrete is in a 12 in × 8 ft column?
π × 0.5² × 8 = 6.28 ft³ = 0.23 yd³, about 11 bags of 80 lb mix.
Why does a small change in diameter matter so much?
Volume grows with the square of the diameter. A 16 in column holds about 1.78 times as much as a 12 in column.
Bag yields: 0.30 / 0.45 / 0.60 ft³ for 40 / 60 / 80 lb standard concrete mix (manufacturer data sheets). The concrete guide has the formulas and worked examples.
Sources
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