Concrete Column Calculator
Calculate concrete volume for any round or square column, pier or pillar. Get volume, premix bag count and cost estimate instantly. Used for verandah posts, structural columns and bridge piers.
🔨 Concrete Column Calculator
📐 How It Works
Column volume is cross-sectional area multiplied by height. Round columns use π×r². Square columns use width×depth. Multiply by the number of columns and add waste for formwork losses and over-pour.
📋 Worked Example
6 round columns, 500mm diameter, 3.5m tall: Area = π×0.25² = 0.196 m². Each = 0.196×3.5 = 0.687 m³. Total × 6 = 4.12 m³. With 10% waste = 4.53 m³.
❓ Frequently Asked Questions
Structural columns in residential construction: minimum N25 (25 MPa). Commercial or engineer-specified: N32–N40. Columns must be designed by a structural engineer who will specify concrete strength, reinforcement and formwork requirements. Never guess on structural elements.
Yes — structural concrete columns always need vertical rebar (typically N16–N32 bars) and horizontal ties or spirals (N10 or N12). The reinforcement cage is placed before concrete is poured. Follow the engineer's drawing exactly — column reinforcement is critical for structural performance.
Round column formwork options: cardboard tube forms (Sonotube) for one-off use, steel or fibreglass reusable forms for multiple pours. Strip cardboard tubes after 24–48 hours. Reusable forms can often be stripped after 12–24 hours in warm conditions. Apply release agent before pouring.
Keep fresh concrete columns moist for at least 7 days. Cover exposed tops with wet hessian or plastic. In hot or windy conditions, cure the sides too by wrapping with wet hessian. Proper curing dramatically improves final strength — uncured concrete can lose 30–40% of its potential strength.