Concrete Column Calculator

What Is a Concrete Column or Cylinder?

This concrete cylinder calculator handles any vertical or horizontal cylindrical concrete element — deck piers, sonotube footings, structural columns, porch supports, and post bases are the most common residential applications. Round columns are formed using cylindrical cardboard tube forms (sonotubes) that hold wet concrete in shape while it cures, then peel away. They are stronger per unit volume than square columns of the same cross-sectional area and are easier to form in the field.

For residential deck footings, 10–12 inch diameter cylinders at 36–48 inch depth are standard. Structural columns in commercial construction follow ACI 318 minimum requirements — 1% longitudinal steel ratio, 3,000 PSI minimum concrete, and ties or spiral reinforcement to confine the core. Sizing for residential applications is driven by the tributary load, soil bearing capacity, and local frost depth.

How to Use This Concrete Cylinder Calculator

This concrete cylinder calculator (also used as a concrete column calculator) estimates the volume of concrete needed for any cylindrical shape — round columns, piers, deck footings, and sonotubes. Enter the diameter and height of the cylinder in inches or feet and get instant results in cubic yards, cubic feet, and the number of bags required. For poured slabs and footings, see our concrete calculator.

Concrete Cylinder Volume Formula

The formula for the volume of a cylinder is V = π × r² × h, where r is the radius (half the diameter) and h is the height. Both measurements must be in the same unit — feet when calculating for concrete.

To convert to cubic yards (the unit concrete is ordered in), divide the cubic-foot result by 27.

Step-by-Step Example

1. A round column is 12 inches in diameter and 8 feet tall
2. Convert diameter to radius in feet: 12 in ÷ 12 = 1 ft diameter → radius = 0.5 ft
3. Apply the formula: π × (0.5)² × 8 = 3.14159 × 0.25 × 8 = 6.28 ft³
4. Convert to cubic yards: 6.28 ÷ 27 = 0.233 yd³
5. Add 10% waste: 0.233 × 1.10 = 0.256 yd³ to order

Common Cylinder Sizes and Concrete Volumes

Here are ready-to-use estimates for frequently encountered column and pier sizes:

• 8 in dia × 3 ft deep — 0.047 yd³ / 1.26 ft³ / ~3 bags (60 lb)
• 10 in dia × 3 ft deep — 0.061 yd³ / 1.64 ft³ / ~4 bags (60 lb)
• 12 in dia × 4 ft deep — 0.116 yd³ / 3.14 ft³ / ~7 bags (60 lb)
• 16 in dia × 4 ft deep — 0.207 yd³ / 5.59 ft³ / ~13 bags (60 lb)
• 18 in dia × 5 ft deep — 0.368 yd³ / 9.94 ft³ / ~23 bags (60 lb)

Always add at least 10% to your calculated volume to account for uneven excavation, spillage, and overpouring at the top.

Tips for Pouring Round Concrete Columns and Piers

• Use sonotube forms — cylindrical cardboard forms hold the concrete in shape while it cures and peel away cleanly; see our sonotube calculator for tube-specific estimates
• Extend the tube above grade — pour sonotubes 2–4 inches above the final grade so water drains away from the column base
• Add rebar — insert at least one #4 or #5 rebar vertically through the center for structural columns; use two or more for heavily loaded piers
• Check plumb before the concrete sets — use a level on two sides to ensure the form is perfectly vertical
• Use fast-setting concrete for speed — products like Quikrete Fast-Setting can allow post setting within 20–40 minutes

How Much Does a Concrete Cylinder Cost?

The cost of a concrete cylinder depends on its size and whether you use bag concrete or ready-mix. Here are material cost estimates using average 2025–2026 pricing:

• 8 in dia × 3 ft (deck pier) — 0.047 yd³ — about $6–$8 in bag concrete (2 bags of 80 lb)
• 12 in dia × 4 ft (structural pier) — 0.116 yd³ — about $40–$55 in bag concrete (6 bags of 80 lb)
• 18 in dia × 5 ft (heavy footing) — 0.368 yd³ — about $120–$150 in bag concrete (19 bags of 80 lb)
• 24 in dia × 8 ft (large column) — 1.05 yd³ — ready-mix at $130/yd³ is more economical at ~$137 vs. $260+ in bags

For single piers and small footings, bag concrete is the most practical choice. Once you need more than about 0.75 cubic yards (roughly 30 bags of 80 lb), ready-mix delivery becomes both cheaper and far less labor-intensive. Use our concrete cost calculator to compare options for your project.