Find the width you need for a set height.
⚙️Calculation Parameters
📊Calculated Output
How Target Volume Diameter Calculator Works?
To solve for diameter, the Target Volume Diameter Calculator reverses the cylinder formula: you enter a volume and a height, and the tool returns the diameter. The process takes 4 steps.
Enter the target volume
Type the concrete volume the pier needs, in cubic feet (ft³), cubic yards (yd³), liters (L) or cubic meters (m³).
Enter the fixed height
Type the depth set by frost line, grade or form length.
Solve the radius
The calculator divides volume by π × h and takes the square root.
Round to a stock size
The tool doubles the radius and rounds up to the next stock tube size: 6, 8, 10, 12, 14, 16, 18 or 24 in.
Target Volume Diameter Calculator Formula
The Target Volume Diameter Calculator rearranges V = π × r² × h to isolate the diameter.
Radius from volume
r = √(V ÷ (π × h))V and h in matching units, such as ft³ and ft.
Diameter in inches
D (in) = 24 × √(V (ft³) ÷ (π × h (ft)))24 converts the radius in feet to a diameter in inches.
Stock size
D stock = next size ≥ DRounding up keeps the volume at or above the target.
Worked example: 3 ft³ needed in a 48 in deep hole
- h = 4 ft, so r = √(3 ÷ (3.1416 × 4)) = √0.2387 = 0.4886 ft
- D = 0.4886 × 24 = 11.73 in
- Round up to a 12 in tube, which holds 3.14 ft³
Target Volume Diameter Calculator Conversion Table
The target diameter conversion table lists the exact diameter required for 6 target volumes at 3 heights.
| Target volume | Diameter at 36 in | Diameter at 48 in | Diameter at 60 in |
|---|---|---|---|
| 1.0 ft³ (28 L) | 7.8 in | 6.8 in | 6.1 in |
| 2.0 ft³ (57 L) | 11.1 in | 9.6 in | 8.6 in |
| 3.0 ft³ (85 L) | 13.5 in | 11.7 in | 10.5 in |
| 4.0 ft³ (113 L) | 15.6 in | 13.5 in | 12.1 in |
| 5.0 ft³ (142 L) | 17.5 in | 15.1 in | 13.5 in |
| 6.0 ft³ (170 L) | 19.1 in | 16.6 in | 14.8 in |
Round each value up to the next stock tube size before buying forms.
What is Target Volume Diameter Calculator?
A Target Volume Diameter Calculator is a reverse cylinder calculator that finds the tube diameter needed to hold a set concrete volume at a fixed height.
Engineers sometimes specify a pier by volume or by bearing area, while the depth is fixed by the frost line. The calculator answers which tube size meets that volume at that depth. A 4 ft³ pier at 48 in deep needs a 13.5 in diameter, so a 14 in tube is the smallest stock size that works.
The tool pairs with the Target Volume Height Calculator, which solves the opposite case with a fixed diameter.
What are the uses of Target Volume Diameter Calculator?
There are 4 main uses of the Target Volume Diameter Calculator.
Bearing design
Designers pick a tube size that meets a minimum concrete volume at code depth.
Leftover concrete
Crews pick a tube size that uses a known extra volume in one form.
Shallow-depth limits
Builders on rock or a shallow utility find the wider tube that keeps the volume.
Stock planning
Suppliers see which diameters cover a range of target volumes.
🔗Related Sonotube Calculators
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Target Volume Height Calculator
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Tapered Pier Volume Calculator
Get the volume of a pier that tapers.