Estimate concrete for cylindrical forms
Sonotube Concrete Calculator
Use this Sonotube concrete calculator with the form’s inside diameter, concrete fill height, and number of identical tubes. Review the volume in cubic yards or cubic metres and compare bag equivalents using the selected product yield.
Round hole estimate
Measurement system: Imperial. Planning estimate based on the dimensions and allowance shown below.
Build your estimate
Choose a shape, enter measured dimensions, then review every step.
Enter the dimensions of the concrete itself. This estimate does not subtract posts or wall openings.
Bag yields and product settings
Yield differs by product. These common examples are editable.
Bag counts are rounded up. The 40, 50, 60, and 80 lb rows show common US products; use the package yield for your product.
Optional: price your materials
Enter local prices. No regional or supplier price is assumed.
Material estimate only. Delivery, taxes, labor, and supplier minimums are not included.
Calculation and assumptions
Cylinder volume
Worked example: one 12 in inside-diameter tube, 4 ft fill height
- Convert the 12 in diameter to 1 ft; the radius is 0.5 ft.
- Net volume = π × 0.5² × 4 = 3.14 ft³, or 0.116 yd³.
- With a chosen 10% allowance, plan for about 0.128 yd³.
Measure the form and concrete fill
- Use the actual inside diameter; product sizes and form walls can vary.
- Enter only the concrete fill height, not the full tube length if the tube is only partly filled.
- The estimate treats each form as a straight cylinder and does not subtract a post, rebar cage, or other displacement.
All example quantities are geometry and arithmetic illustrations. Confirm measurements, product yields, ordering rules, and project requirements with your plans and supplier.