How to use it
- Enter the tube diameter in inches.
- Enter the depth in feet.
- Enter how many tubes you plan to pour.
- Read the bag, cubic yard, and cubic foot totals.
What it does – The calculator takes the diameter of a Sonotube, its depth, and the number of columns you need, then instantly gives you the total volume in cubic feet, converts that to cubic yards, and tells you how many standard 80‑lb bags are required (each bag = 0.6 ft³). Why it matters – Knowing the exact material amount prevents costly over‑ordering and avoids running short mid‑project. How to read the results – The Cubic Feet line is the raw volume of concrete. Divide by 27 to see Cubic Yards, the unit most suppliers quote. Multiply the cubic‑foot total by 1⁄0.6 (or divide by 0.6) to get the Bag count; round up to the next whole bag. The calculator also shows the total for the quantity you entered, so you can plan for multiple footings at once. All results update instantly as you change any input.
Pro tips
- Add 5‑10% extra bags for spillage and settling.
- Round up bag count; you can’t order a fraction of a bag.
- Order bags in full pallets to reduce shipping cost when you need many.
- Double‑check diameter and depth; a common mistake is using radius instead of diameter.
Real-life examples
- A homeowner building a 4‑ft fence post footing with 12‑in Sonotubes.
- A contractor estimating concrete for a row of 8‑in driveway columns.
- A landscape designer planning a garden wall with 10‑in decorative footings.
Case study
Mike needed 6 footings, each 12 in diameter and 3 ft deep. The calculator showed 108 cubic ft, 4 cubic yds, and 180 bags. He ordered 180 bags, saved $200 on excess material, and finished on schedule.