Sonotube Concrete Calculator
Plan round form-tube pours without guessing from a flat slab formula. Enter the inside diameter and actual concrete fill height for each tube.
How the calculation works
For each solid cylinder, volume in cubic feet = π × (inside diameter in feet ÷ 2)² × fill height in feet. Multiply by the number of identical tubes, then divide by 27 for cubic yards.
Worked example
Four tubes with a 12 in inside diameter and 4 ft of concrete fill need about 12.57 ft³, or 0.47 yd³ before extra. With 10% extra, plan for about 0.51 yd³ or 24 bags at 0.60 ft³ per 80 lb bag.
Before you order
Use the tube’s inside diameter, not the outside label dimension. This estimates a full, solid tube only; it does not size a footing bell or account for displaced steel. Your project plans determine depth and reinforcement.
Review the calculation method and source notes, then use the supplier checklist before placing an order.
Continue planning
Content and calculator by pourmeasure. Formula and assumption notes: methodology and sources. Updated October 2026. No independent engineering review is claimed.