Supply MathConcrete per foot of depth (no waste)
| Tube diameter | ft³ per ft | 80 lb bags per ft | 60 lb bags per ft |
|---|---|---|---|
| 6 in | 0.2 | 0.33 | 0.44 |
| 8 in | 0.35 | 0.58 | 0.78 |
| 10 in | 0.55 | 0.91 | 1.21 |
| 12 in | 0.79 | 1.31 | 1.75 |
| 16 in | 1.4 | 2.33 | 3.1 |
| 18 in | 1.77 | 2.95 | 3.93 |
| 24 in | 3.14 | 5.24 | 6.98 |
Multiply by the depth of each tube, then round up to whole bags for the job.
Frequently asked questions
How many bags of concrete for a 12 inch sonotube?
A 12 in tube holds about 0.79 ft³ per foot of depth, so roughly 1.3 bags of 80 lb concrete per foot. A 4 ft deep 12 in pier takes about 6 bags of 80 lb.
How many bags of concrete per fence post?
A typical fence post hole is 3 times the post width and about 1/3 of the post height deep. A 10 in × 2.5 ft hole is about 1.36 ft³, roughly 2–3 bags of 80 lb mix minus the volume of the post itself.