Concrete Column Calculator
Columns are the backbone of any elevated structure, and getting the concrete volume right means no mid-pour trips to the supply yard. Enter your column dimensions, choose round or square, and this calculator gives you exact cubic yards, bag counts, and rebar estimates for every column in your project.
Column Volume Formulas
Round column: V = pi x r² x h (where r = diameter / 2)
Square column: V = side² x h
Both formulas give volume in cubic feet. Divide by 27 for cubic yards.
Standard Column Sizes
Residential and light commercial columns typically fall into these ranges:
- Deck posts: 8-12" round sonotube
- Porch columns: 12-16" round or 12x12 square
- Structural columns: 16-24" round, 12x12 to 24x24 square
- Heavy commercial: 24-36" or larger
Rebar Requirements
Most building codes require a minimum of 4 vertical bars in concrete columns. The typical setup:
- 4 bars -- Standard for residential columns
- 6-8 bars -- Larger columns or higher load requirements
- Ties -- Horizontal rebar loops spaced every 12-18" to hold vertical bars in place
Standard concrete cover for rebar is 3 inches from the outside face of the column. This protects the steel from moisture and corrosion.