How to use it
- Enter the tube diameter in inches (12).
- Enter the depth in feet.
- Enter the quantity of tubes you’ll pour.
- Read cubic yards, cubic feet, and bag count.
This calculator tells you exactly how many 80‑lb bags of concrete mix you’ll need to fill a 12‑inch sonotube of any depth and quantity. Knowing the cubic yards lets you compare bids, while the bag count helps you order the right amount without over‑buying. Just input the tube’s diameter (12 inches is preset), the depth in feet, and how many tubes you plan to pour. The results appear instantly in three units: cubic yards for contractor estimates, cubic feet for on‑site volume checks, and the number of 80‑lb bags based on the standard 0.6 ft³ per bag. Use the numbers to budget, schedule deliveries, and avoid costly waste.
Pro tips
- Add a 10% waste allowance to the bag total.
- Always round up to the next whole bag; you can’t buy a fraction.
- Order one extra bag for spillage or mix errors.
- Confirm the tube length matches your design before calculating.
Real-life examples
- Homeowner pouring footings for a new deck.
- Contractor estimating material for a driveway strip trench.
- DIYer building a raised garden bed with concrete footings.
Case study
Mike needed 4 sonotubes 3 ft deep for a patio. The calculator showed 2.4 cubic yards, 128 cubic feet, and 213 bags. He ordered 220 bags, avoiding a second delivery and saving $150.