How to use it
- Pick the tube diameter.
- Enter the full height of concrete in each tube, including the part below grade.
- Enter the number of piers.
The formula
Volume per pier = π × (diameter ÷ 2)² × height
Total = volume per pier × number of piers
Worked example
| Tube diameter | 12 in |
| Height of each column | 48 in |
| Number of columns | 4 |
| Waste / spillage allowance | 10 % |
Result
| Concrete needed | 0.51 cubic yards |
| Cubic feet | 13.8 ft³ |
| Cubic meters | 0.39 m³ |
| 80 lb bags | 24 bags |
| 60 lb bags | 31 bags |
| Approx. weight | 1 tons |
| 80 lb bags per column | 6 bags |
Tips before you order
- An 8 in tube holds about 0.35 ft³ per foot of height; a 12 in tube holds 0.79 ft³ per foot.
- Flared footing bases under the tube add concrete — calculate them separately.
Questions
How many bags of concrete for a 12 inch Sonotube?
A 12 in tube 4 ft tall holds 3.14 ft³ — about 6 bags of 80 lb concrete.
How many bags for an 8 inch Sonotube?
An 8 in tube 4 ft tall holds 1.4 ft³ — about 3 bags of 80 lb concrete.