Get the volume from the distance around the tube.
⚙️Calculation Parameters
📊Calculated Output
How Circumference-Based Sonotube Calculator Works?
To calculate volume from circumference, the Circumference-Based Sonotube Calculator converts a tape wrap around the tube into area and volume. The process takes 4 steps.
Wrap a tape around the form
Pull a flexible tape around the outside of the tube at mid-height and read the circumference (C).
Subtract wall thickness
Enter the wall thickness, if known. Most fiber forms have walls 0.1 in to 0.4 in (3 mm to 10 mm) thick, which shrinks the inside circumference.
Convert to area
The calculator turns C into the circle area with A = C² ÷ (4π).
Multiply by height
Area times fill height gives the volume in cubic feet (ft³), cubic yards (yd³) and liters (L).
Circumference-Based Sonotube Calculator Formula
The Circumference-Based Sonotube Calculator replaces radius with circumference in the cylinder formula.
Area from circumference
A = C² ÷ (4 × π)Derived from C = 2πr and A = πr².
Volume
V = C² × h ÷ (4 × π)C and h in the same length unit.
Inside circumference
C_in = C_out − 2π × tt is the wall thickness.
Worked example: tape reads 37.7 in, wall 0.2 in, height 48 in
- C_in = 37.7 − 2 × 3.1416 × 0.2 = 36.44 in
- A = 36.44² ÷ 12.566 = 105.7 in² = 0.7339 ft²
- V = 0.7339 × 4 ft = 2.936 ft³
Circumference-Based Sonotube Calculator Conversion Table
The circumference conversion table maps 8 tape readings to the matching diameter, area and fill volume.
| Inside circumference | Diameter | Area (ft²) | ft³ per 12 in | ft³ at 48 in |
|---|---|---|---|---|
| 18.85 in (47.9 cm) | 6.0 in | 0.1964 | 0.196 | 0.79 |
| 25.13 in (63.8 cm) | 8.0 in | 0.3490 | 0.349 | 1.40 |
| 31.42 in (79.8 cm) | 10.0 in | 0.5456 | 0.546 | 2.18 |
| 37.70 in (95.8 cm) | 12.0 in | 0.7854 | 0.785 | 3.14 |
| 43.98 in (111.7 cm) | 14.0 in | 1.0689 | 1.069 | 4.28 |
| 50.27 in (127.7 cm) | 16.0 in | 1.3965 | 1.397 | 5.59 |
| 56.55 in (143.6 cm) | 18.0 in | 1.7672 | 1.767 | 7.07 |
| 75.40 in (191.5 cm) | 24.0 in | 3.1417 | 3.142 | 12.57 |
Readings match the inside circumference of 6 in to 24 in tubes.
What is Circumference-Based Sonotube Calculator?
A Circumference-Based Sonotube Calculator is a concrete volume tool that uses a tape measurement around a round form or column instead of a diameter.
A tape wrap is the most accurate field reading on a tube that is already set, braced or backfilled. A diameter reading across the top of a tube can miss center by 0.5 in, while a wrap captures the full perimeter. The calculator converts that perimeter into volume.
The tool handles out-of-round forms well. A form squeezed into an oval keeps nearly the same perimeter, so the wrap gives a closer volume than one diameter reading.
What are the uses of Circumference-Based Sonotube Calculator?
There are 4 main uses of the Circumference-Based Sonotube Calculator.
Set and braced forms
Crews measure tubes already plumbed in holes without removing braces.
Existing columns
Inspectors measure cured round columns for repair jackets or volume records.
Oval forms
Installers check forms pushed out of round by backfill pressure.
Pipe and casing forms
Builders size fills inside culvert pipes and steel casings measured by wrap.
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