How to use it
- Enter the tube diameter in inches, depth in feet, and quantity needed.
- Click Calculate to see cubic feet, cubic yards, and 80‑lb bag count.
- Round up the bag number and use it to order your concrete.
What it does – The calculator takes the Sonotube diameter, depth and quantity and instantly gives you the total volume in cubic feet, the equivalent cubic yards, and the number of 80‑lb bags required. Why it matters – Knowing the exact material amount prevents over‑ordering, saves money, and ensures the footing is poured with the right strength. How to read the results – Cubic feet is the raw volume, divide by 27 to see cubic yards (the unit most suppliers quote), and divide cubic feet by 0.6 to see how many 80‑lb bags you’ll need. Use the rounded‑up bag count for ordering to cover minor waste. The tool also helps you compare different tube sizes or depths without manual math. When you change any input, the figures update in real time, so you can experiment with design tweaks and see material impact instantly.
Pro tips
- Add 5‑10% extra bags for spillage and compaction.
- Round up bag count; you can’t buy a fraction of a bag.
- Order bags in full pallets to get bulk discounts.
- Double‑check diameter conversion; inches to feet is 12 inches per foot.
Real-life examples
- A DIY homeowner building a 16‑in fence post footing.
- A small contractor estimating concrete for multiple Sonotube piers on a shed foundation.
- A landscaper preparing footings for a pergola with 16‑in Sonotubes.
Case study
John needed three 16‑in Sonotube footings 4 ft deep. Using the calculator he saw he required 1.57 ft³ of concrete, 0.06 yd³, and 3 bags. He ordered three 80‑lb bags, saved $15 on excess material, and completed the job on schedule.