Concrete Column Calculator

A concrete column calculator sizes round columns or piers — the vertical concrete in a porch post, a structural column or a pier. Enter the diameter, the height and how many you are pouring, and it returns the total volume plus the volume of each individual column.

Your measurements

Result

Round columns are usually poured inside a cardboard tube form (a Sonotube). If that is what you are building, the sonotube calculator is the same maths with notes specific to tube forms and footings.

How it is calculated

A round column is π·r²·height, where the radius is half the diameter. We multiply by the number of columns, then convert to cubic yards or metres and bag counts and add 10% waste for spillage at the top of each form.

Steps

Enter the column diameter in inches.
Enter the finished height in feet.
Enter how many identical columns you are pouring.
Read the total volume and the per-column figure.
Use the bag count for one or two columns; order ready-mix for a row of them.

Worked example

Four 12-inch columns, each 9 ft tall, hold about 7.1 cubic feet of concrete each — roughly 28 cubic feet or 1.05 cubic yards in total before waste.

Common questions

How do I work out concrete for a round column?

Area of the circle (π·r²) times the height, times the number of columns. The calculator does this and converts to yards, metres and bags.

What is a Sonotube?

A cardboard tube form you stand up and fill with concrete to cast a round column or pier. Our sonotube calculator covers tube footings specifically.

Should columns be reinforced?

Structural columns and piers almost always have vertical rebar tied into the footing. Reinforcement comes from the structural design.

How much waste for columns?

Ten percent is sensible — concrete tends to spill at the top of a tall form, and you do not want to run a column short.