Sonotube Concrete Calculator
This Sonotube concrete calculator finds the volume of concrete for cylindrical tube forms, piers, and columns. As a concrete cylinder calculator it takes the tube diameter, the height, and the number of tubes and returns cubic yards, cubic feet, and bag counts — exactly what you need for deck footings, porch columns, and pier foundations.
How to use this calculator
- Enter the tube diameter (the inside diameter of the form).
- Enter the height — the length of tube you will fill with concrete.
- Set the number of tubes for the whole project.
- Add a waste allowance and read the bag count or cubic yards.
The formula
A tube is a cylinder, so its volume is π times the radius squared times the height. The radius is half the diameter. Multiply by the number of tubes:
Cubic feet = π × (Diameter ft ÷ 2)² × Height ft × Tubes
Worked example. A 12 inch tube (1 ft diameter, 0.5 ft radius) that is 4 ft tall: 3.1416 × 0.5² × 4 = 3.14 cubic feet, about 0.12 cubic yards — roughly 6 × 80 lb bags. Four such piers need about 12.6 cubic feet.
Frequently asked questions
How much concrete does a Sonotube hold?
Use the cylinder formula: volume = π × radius² × height. A 12 inch tube 4 feet tall holds about 3.14 cubic feet, or roughly 6 × 80 lb bags.
How many bags of concrete for a 12 inch Sonotube?
A 12 inch diameter tube uses about 0.79 ft³ per foot of height, so a 4 foot pier needs about 3.14 ft³ — around 6 × 80 lb bags or 8 × 60 lb bags.
What is a Sonotube?
Sonotube is a brand of waxed cardboard tube used as a one-time form for round concrete columns, piers, and footings. This is an independent calculator for any cylindrical form.
How do I calculate cylinder concrete volume?
Convert the diameter to feet, halve it for the radius, square the radius, multiply by π (3.1416), then multiply by the height in feet. Multiply by the number of tubes for the total.