Sonotube Concrete Calculator
Sonotube concrete calculator for piers, posts, and round footings.
Estimate concrete for sonotube forms, round piers, deck footings, fence post holes, pole barn post footings, and cylindrical concrete columns. Use the main concrete calculator to enter diameter, depth, quantity, waste, and concrete price.
How to calculate concrete for a sonotube
A sonotube or round pier is calculated like a cylinder. Convert the tube diameter into a radius, square the radius, multiply by pi, then multiply by depth and quantity.
Formula
π × Radius² × Depth × Quantity = Concrete Volume
For imperial estimates, diameter is commonly entered in inches and depth in feet. The calculator converts the result into cubic feet and cubic yards. For metric estimates, diameter is entered in centimeters and depth in meters.
Sonotube concrete example
Four round piers with a 12 inch diameter and 3 ft depth require about 9.42 cubic feet of concrete. Since one cubic yard equals 27 cubic feet, that is about 0.35 cubic yards before waste. With 10% waste, the estimate is about 0.38 cubic yards.
Sonotube calculator FAQ
What measurements do I need for a sonotube estimate?
You need the tube diameter, depth or height, quantity of tubes, waste percentage, and concrete price.
Is a sonotube calculated as a cylinder?
Yes. A sonotube is a cylindrical form, so the volume formula uses pi times radius squared times depth.
Can this be used for fence post holes?
Yes. Use the Round Pier / Sonotube mode in the main concrete calculator and enter the hole diameter, depth, and quantity.
Does this include the post volume?
No. This estimate assumes the hole or tube is filled with concrete. If a post displaces concrete volume, the actual amount may be slightly lower.