How to use it
- Enter the tube diameter in inches.
- Enter the depth in feet.
- Enter the quantity of tubes you need.
- Read the cubic yards, 80‑lb bags, and cubic feet results.
What it does – The Sonotube calculator turns the simple dimensions you input (diameter, depth, and quantity) into three concrete measures you can order: cubic yards, 80‑lb bags, and cubic feet. Knowing the exact cubic yards helps you compare prices from suppliers, while the bag count tells you how many 80‑lb sacks to purchase. The cubic‑feet figure is useful for on‑site planning and confirming that the mix will fill the tubes completely. The tool uses the standard conversion that one 80‑lb bag yields about 0.6 ft³ and that one cubic yard equals 27 ft³, so the results are reliable for any standard Sonotube size. Just plug in your numbers and get an instant, accurate estimate. You can also adjust the quantity to see how bulk orders affect the bag total, making it easy to budget and avoid surprise shortages. The calculator works on any device, so you can check your numbers while on the job site or in the office.
Pro tips
- Add a 10% waste allowance to cover spillage and settling.
- Always round up the bag count; you can’t buy a fraction of a bag.
- Order a few extra bags to handle unexpected depth changes.
- Double‑check that diameter is entered in inches and depth in feet.
Real-life examples
- Building a new patio with 12‑in Sonotube footings.
- Installing a garage foundation using 8‑in tubes.
- Repairing a fence post footing and need exact mix.
Case study
Mike needed 4 × 12‑in footings 2 ft deep. The calculator showed 0.23 yd³, 11 bags, and 6.3 ft³. He ordered 11 bags, avoided a costly over‑order and finished on schedule.