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.
Piers are usually one line on a bigger estimate. The concrete estimate guide covers how to total yards, bags, and cost across a whole project.
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.