Concrete Sonotube Footing Calculator
Concrete for round tube footings: π × (d ÷ 2)² × depth per tube, in cubic feet and yards, with 40, 50, 60 and 80 lb bag counts rounded up. How it works
Use the Concrete Sonotube Footing Calculator
About the Concrete Sonotube Footing Calculator
A 12 in tube 48 in deep holds 3.14 cubic feet of concrete, 0.116 cubic yards: 6 bags of 80 lb or 7 bags of 60 lb, rounded up. The Sonotube footing calculator uses π × (diameter ÷ 2)² × depth per tube, times the number of tubes plus any extra allowance, and the bag yields printed on the QUIKRETE Concrete Mix No. 1101 data sheet.
Concrete for one tube 48 in deep
| Tube diameter | Cubic feet | Cubic yards | 80 lb bags | 60 lb bags | 50 lb bags | 40 lb bags |
|---|---|---|---|---|---|---|
| 6 in | 0.79 | 0.029 | 2 | 2 | 3 | 3 |
| 8 in | 1.40 | 0.052 | 3 | 4 | 4 | 5 |
| 10 in | 2.18 | 0.081 | 4 | 5 | 6 | 8 |
| 12 in | 3.14 | 0.116 | 6 | 7 | 9 | 11 |
| 14 in | 4.28 | 0.158 | 8 | 10 | 12 | 15 |
| 16 in | 5.59 | 0.207 | 10 | 13 | 15 | 19 |
| 18 in | 7.07 | 0.262 | 12 | 16 | 19 | 24 |
| 24 in | 12.57 | 0.465 | 21 | 28 | 34 | 42 |
No extra allowance. Bags are rounded up, so for several tubes enter the count: the calculator rounds the total, which can take fewer bags than one tube’s count times the number of tubes.
Cubic yards and 80 lb bags per tube, by diameter and depth
| Tube diameter | 12 in deep | 24 in deep | 36 in deep | 48 in deep | 60 in deep |
|---|---|---|---|---|---|
| 6 in | 0.007 yd³, 1 bag | 0.015 yd³, 1 bag | 0.022 yd³, 1 bag | 0.029 yd³, 2 bags | 0.036 yd³, 2 bags |
| 8 in | 0.013 yd³, 1 bag | 0.026 yd³, 2 bags | 0.039 yd³, 2 bags | 0.052 yd³, 3 bags | 0.065 yd³, 3 bags |
| 10 in | 0.020 yd³, 1 bag | 0.040 yd³, 2 bags | 0.061 yd³, 3 bags | 0.081 yd³, 4 bags | 0.101 yd³, 5 bags |
| 12 in | 0.029 yd³, 2 bags | 0.058 yd³, 3 bags | 0.087 yd³, 4 bags | 0.116 yd³, 6 bags | 0.145 yd³, 7 bags |
| 14 in | 0.040 yd³, 2 bags | 0.079 yd³, 4 bags | 0.119 yd³, 6 bags | 0.158 yd³, 8 bags | 0.198 yd³, 9 bags |
| 16 in | 0.052 yd³, 3 bags | 0.103 yd³, 5 bags | 0.155 yd³, 7 bags | 0.207 yd³, 10 bags | 0.259 yd³, 12 bags |
| 18 in | 0.065 yd³, 3 bags | 0.131 yd³, 6 bags | 0.196 yd³, 9 bags | 0.262 yd³, 12 bags | 0.327 yd³, 15 bags |
| 20 in | 0.081 yd³, 4 bags | 0.162 yd³, 8 bags | 0.242 yd³, 11 bags | 0.323 yd³, 15 bags | 0.404 yd³, 19 bags |
| 24 in | 0.116 yd³, 6 bags | 0.233 yd³, 11 bags | 0.349 yd³, 16 bags | 0.465 yd³, 21 bags | 0.582 yd³, 27 bags |
| 30 in | 0.182 yd³, 9 bags | 0.364 yd³, 17 bags | 0.545 yd³, 25 bags | 0.727 yd³, 33 bags | 0.909 yd³, 41 bags |
| 36 in | 0.262 yd³, 12 bags | 0.524 yd³, 24 bags | 0.785 yd³, 36 bags | 1.047 yd³, 48 bags | 1.309 yd³, 59 bags |
One tube, no extra allowance. Bags are 80 lb bags of QUIKRETE Concrete Mix No. 1101 at 0.60 cubic feet each, rounded up.
Frequently asked questions
- How many bags of concrete do I need for a Sonotube?
- Divide the tube volume by the bag yield and round up. A 10 in tube 42 in deep is 1.91 cubic feet: 4 bags of 80 lb, 5 of 60 lb, 6 of 50 lb or 7 of 40 lb. The first table on this page gives every bag size for 48 in deep tubes from 6 to 24 in across; the second gives cubic yards and 80 lb bags for tubes 6 to 36 in across and 12 to 60 in deep.
- How much concrete do I need for deck footings?
- Nine 10 in tubes 42 in deep hold 17.18 cubic feet. With a 10% allowance that is 18.90 cubic feet, 0.700 cubic yards or 32 bags of 80 lb, against 29 bags with no allowance.
- How many cubic feet does an 80 lb bag of concrete make?
- About 0.60 cubic feet, by the QUIKRETE Concrete Mix No. 1101 data sheet. A 60 lb bag makes 0.45, a 50 lb bag 0.375 and a 40 lb bag 0.30 cubic feet. Other mixes yield differently, so check the bag.
- When should I order ready-mix instead of bags?
- The calculator suggests it from 21 tubes. For ordering it shows cubic yards: 20 tubes of 12 × 48 in are 62.83 cubic feet, 2.327 cubic yards, or 105 bags of 80 lb.
- How much extra concrete should I allow?
- The extra allowance field adds a percentage to the total before the bags are counted; it is 0 by default. The tube volume does not include a flared base, the hole below the tube or spillage, so add for those yourself.
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