Add up the tube length you need.
⚙️Calculation Parameters
📊Calculated Output
How Sonotube Form Length Calculator Works?
To total form length, the Sonotube Form Length Calculator adds the cut length of every pier for each tube diameter. The process takes 4 steps.
Enter each pier
Type the diameter and the full form length: depth below grade plus reveal above.
Group by diameter
The calculator sorts piers by tube size, since each size is bought separately.
Sum lengths
The tool totals linear feet (ft) and meters (m) per diameter.
Compare with stock
The calculator shows the 12 ft (3.66 m) and 4 ft (1.22 m) tubes that cover each total.
Sonotube Form Length Calculator Formula
The Sonotube Form Length Calculator sums lengths by diameter.
Total length
L_D = Σ nᵢ × hᵢFor all piers of diameter D.
12 ft tubes
T₁₂ ≥ ⌈L_D ÷ 12⌉Lower bound; cutting losses can add one.
4 ft tubes
T₄ = n, if hᵢ ≤ 48 inOne short tube per pier.
Worked example: 9 piers at 12 in, 54 in long each
- L = 9 × 54 = 486 in = 40.5 ft (12.34 m)
- 12 ft tubes ≥ ⌈40.5 ÷ 12⌉ = 4 (2 cuts of 54 in fit per 12 ft tube, so 5 tubes are needed)
- 4 ft tubes cannot cover a 54 in pier without splicing
Sonotube Form Length Calculator Conversion Table
The form length conversion table lists 6 pier groups with total linear length and the tube counts in 12 ft and 4 ft stock.
| Diameter | Piers | Length each | Total length | 12 ft tubes (min) | 4 ft tubes |
|---|---|---|---|---|---|
| 8 in | 12 | 42 in | 42.0 ft (12.80 m) | 4 | 12 |
| 10 in | 8 | 48 in | 32.0 ft (9.75 m) | 3 | 8 |
| 12 in | 9 | 54 in | 40.5 ft (12.34 m) | 4 | — |
| 12 in | 6 | 36 in | 18.0 ft (5.49 m) | 2 | 6 |
| 16 in | 4 | 60 in | 20.0 ft (6.10 m) | 2 | — |
| 18 in | 2 | 72 in | 12.0 ft (3.66 m) | 1 | — |
Minimum 12 ft counts ignore cut layout. Use the Sonotube Cutting Planner for exact cuts.
What is Sonotube Form Length Calculator?
A Sonotube Form Length Calculator is a form tool that totals the linear feet of tube needed for every pier on a job, grouped by diameter.
Tubes are bought by length, not by volume. Long tubes cost less per foot but leave offcuts, and short tubes fit single piers. The calculator gives the total length per size, the first number needed to plan a purchase.
Twelve 8 in piers at 42 in total 42 ft of tube, about 3.5 tubes of 12 ft before cut losses.
What are the uses of Sonotube Form Length Calculator?
There are 4 main uses of the Sonotube Form Length Calculator.
Tube purchases
Builders total length before buying forms.
Size grouping
Estimators split lengths by diameter.
Delivery planning
Contractors check how many 12 ft tubes fit a truck.
Cut planning
Crews feed totals into a cutting plan.
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