Concrete Column Calculator
Deck piers, fence posts, and structural columns all require precise concrete volume calculations. Enter diameter or width, column height, and number of columns to get total cubic yards, bag counts, and cost. Round columns use the formula π × r² × h; square columns use side² × h.
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Top PickQuikrete 80lb Fast-Setting Concrete — Home Depot~$7.48/bag* Affiliate links — we may earn a commission at no cost to you.
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How to Use This Calculator
- 1Enter your measurements in the fields above. Use the units shown next to each field (ft, in, etc.).
- 2Click Calculate to get your material estimate instantly.
- 3Review the highlighted result — it shows the key quantity you need to order.
- 4Use Copy Results to save your estimate, or bookmark the URL — your inputs are encoded in the link.
Pro tip: Always add 10% to your material order to account for waste, cuts, and defects.
Frequently Asked Questions
What size Sonotube do I need for a deck footing?
For a typical 12×12 ft deck bay, a 10-inch or 12-inch diameter Sonotube is standard. The tube diameter should match or exceed the beam width above. A 12-inch tube with fast-setting concrete is the most common choice for deck footings.
How much concrete does a 12-inch column use?
A 12-inch diameter round column 3 feet tall requires approximately 0.087 cubic yards or about 6 bags of 60lb concrete mix. For 4 columns you'd need roughly 24 bags.