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Concrete & Masonry

Sonotube Calculator — How Much Concrete for a Round Column?

Enter the tube diameter and height (in inches) to get the concrete needed for a round column footing or pier — in 80-lb bags and cubic yards.

Units
Concrete needed

How this calculator works

Each tube is a cylinder: volume = π × radius² × height. We total the tubes, then show 80-lb bags (0.6 ft³ each) and cubic yards for ready-mix. Past a few tubes, ready-mix usually wins.

What changes how much you need

  • A 12-inch tube holds about 0.8 ft³ per foot of height (~1.3 bags per foot).
  • Order 10% extra and have it on hand — you can’t pause partway up a column.
  • For more than ~1 cubic yard total, price out ready-mix; bags get expensive and slow.
  • Set anchor bolts or brackets while the concrete is wet.

Frequently asked questions

How much concrete fills a 12-inch Sonotube?

About 0.8 cubic feet per foot of height — roughly 1.3 bags of 80-lb concrete per foot. A 4-ft tube needs about 5 bags.

How many 80-lb bags in a cubic yard?

About 45 (27 ft³ ÷ 0.6 ft³ per bag). Past one yard, ready-mix is cheaper than bags.

Should I order extra?

Yes, about 10%. A column has to be poured in one go, so running short means a weak cold joint.