Round form concrete volume
Concrete Calculator for Round Forms and Sonotubes
Find the raw concrete volume for identical round forms, piers, or columns from the diameter, filled height, and whole number of forms you supply.
Cylindrical volume
Enter your round-form dimensions
Enter diameter in inches, filled height or depth in feet, and a whole-number quantity. This tool calculates volume; it does not design a pier or column.
Enter dimensions and quantity, then calculate.
Methodology 1.0.0 · Calculator 1.0.0
How the round-form calculation works
The calculator converts diameter and height through the shared unit layer, divides diameter by two for radius, calculates π × radius² × height with the shared cylinder geometry, then multiplies by the whole-number quantity.
Verified example
Four 12 in diameter × 4 ft round forms
0.47 yd³12.57 ft³
This fixed example comes from independently derived known-answer case C. It represents four identical right circular cylinders and raw volume without waste.
Measurement tips
- Measure the inside diameter of the round form.
- Enter the actual filled height or depth, not the unfilled form length.
- Count only forms with the same diameter and filled height in one calculation.
- Use dimensions chosen by applicable plans or a qualified professional; this calculator does not determine structural size.
Round Form / Sonotube Formula Reference
Reviewed relationship
The calculator models each form as a right circular cylinder:
radius = diameter ÷ 2
per-form volume = π × radius² × filled height
total volume = per-form volume × whole-number quantity
Diameter and height are normalized through the shared SI unit layer before the shared cylinder function executes. Exact per-form and total volumes are retained; display rounding happens later.
Unit and naming references
The calculator uses the international foot definition: 1 foot is exactly 0.3048 meter and 1 inch is exactly 0.0254 meter. The NIST Guide to the SI, Appendix B documents these relationships and volume conversion factors. Source reviewed 2026-08-26.
Sonoco describes Sonotube® as its concrete-form product family. This site uses “Sonotube” only as a familiar search term alongside the generic “round form” and is not affiliated with or endorsed by Sonoco. Source reviewed 2026-08-26.
Scope and limitations
- The user supplies inside diameter, actual filled height or depth, and a whole-number quantity of identical forms.
- The formula calculates raw geometric volume only; it adds no waste allowance.
- The calculator does not determine required pier diameter, depth, reinforcement, allowable load, soil capacity, or building-code compliance.
- Product dimensions and real placement losses may differ; verify the chosen form and applicable plans.