Concrete Column & Sonotube Calculator
Updated Formulas shown
For deck piers and round columns. Six 12-inch tubes, 4 ft deep, take about 0.73 yd³ — 33 bags of 80 lb with 5% waste.
Concrete for all columns
0.73 yd³
- 80 lb bags
- 330.6 ft³ each
- 80 lb bags
- 33
- 60 lb bags
- 44
- Cubic feet
- 19.79 ft³
- Cubic meters
- 0.56 m³
- Weight (wet)
- 2,969 lb
Includes your waste allowance. Bag yields: 40 lb = 0.30 ft³, 60 lb = 0.45 ft³, 80 lb = 0.60 ft³.
The formula
Volume of a cylinder = π × (diameter ÷ 2)² × height.
Quick reference
| Tube diameter | ft³ per ft | 80 lb bags per ft | Bags for 4 ft |
|---|---|---|---|
| 6 in | 0.196 | 0.33 | 2 |
| 8 in | 0.349 | 0.58 | 3 |
| 10 in | 0.545 | 0.91 | 4 |
| 12 in | 0.785 | 1.31 | 6 |
| 14 in | 1.069 | 1.78 | 8 |
| 16 in | 1.396 | 2.33 | 10 |
| 18 in | 1.767 | 2.95 | 12 |
| 24 in | 3.142 | 5.24 | 21 |
Related calculators
- Concrete CalculatorFree concrete calculator: enter length, width and thickness to get cubic yards, 40/60/80 lb bag counts and ready-mix cost.
- Deck CalculatorFree deck calculator: deck boards, joists at 16 in on center and screws for wood or composite decking.
- Fence Post Concrete CalculatorBags of concrete per fence post: enter hole diameter, depth, post size and number of posts.
Frequently asked questions
How many bags of concrete for a 12 inch Sonotube?
A 12-inch tube holds 0.785 ft³ per foot — about 1.3 bags of 80 lb per foot of depth, so a 4 ft tube needs 6 bags.
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Estimates only. Check quantities with your supplier or contractor before ordering.