Concrete Column & Beam
Calculate concrete for columns and beams. Enter values for instant results with step-by-step formulas.
Formula
Round: V = π x r² x h | Square: V = w x w x h
Calculate volume based on shape. Round columns use circular area formula, square uses width squared, beams use width x depth x length.
Worked Examples
Example 1: Round Column Calculation
Problem:4 round columns, 14\" diameter × 10 feet tall each.
Solution:Diameter: 14\" = 1.167 ft\nRadius: 0.583 ft\nHeight: 10 ft\n\nPer column:\nπ × r² × h = 3.14 × 0.583² × 10 = 10.7 cu ft\n\nTotal for 4:\n10.7 × 4 = 42.8 cu ft\n42.8 ÷ 27 = 1.58 yards\n\nWith 10% waste: 1.74 yards
Result:Order 2 cubic yards for 4 columns
Example 2: Square Beam Calculation
Problem:Beam 12\" × 18\" × 20 feet long.
Solution:Width: 12\" = 1 ft\nDepth: 18\" = 1.5 ft\nLength: 20 ft\n\nVolume = 1 × 1.5 × 20 = 30 cu ft\n30 ÷ 27 = 1.11 cubic yards\n\nWith waste: 1.22 yards
Result:Order 1.5 cubic yards
Example 3: Mixed Column Sizes
Problem:Calculate for 6 columns: 4 at 12\"Ø×8ft and 2 at 16\"Ø×10ft.
Solution:Small columns (12\"Ø × 8'):\nπ × (0.5)² × 8 = 6.28 cu ft each\n4 × 6.28 = 25.1 cu ft\n\nLarge columns (16\"Ø × 10'):\nπ × (0.667)² × 10 = 14.0 cu ft each\n2 × 14.0 = 28.0 cu ft\n\nTotal: 53.1 ÷ 27 = 1.97 yards\nWith waste: 2.16 yards
Result:Order 2.5 cubic yards total
Frequently Asked Questions
What size should my concrete columns be?
Column size depends on load and height. Typical residential: 12\"×12\" to 18\"×18\" square, or 12\"-16\" diameter round. Multi-story may need 16\"×16\" to 24\"×24\". Engineer calculates based on total load and unsupported height. Minimum practical size is 8\"×8\" or 8\" diameter.
What about concrete beams?
Beams are horizontal elements. Common sizes: 12\"×18\", 12\"×24\", or wider for longer spans. Heavily reinforced (multiple bottom bars for tension, stirrups for shear). Volume = width × depth × length. Always designed by engineer for specific loads and spans.
Can I use bagged concrete for columns?
Yes, for small projects (a few columns). For 12\" diameter × 8 ft column, you need about 20 80-lb bags. Practical limit is about 0.5 cubic yards - beyond that, ready-mix is more economical and provides better consistency.
What concrete strength for columns?
Minimum 3,000 PSI for residential columns. 3,500-4,000 PSI for commercial or multi-story. Higher strengths allow smaller column sizes. Structural engineer specifies based on load calculations. Use appropriate mix for your climate (air-entrained in freeze-thaw regions).