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Concrete Tube Calculator

Tube volume = π/4 × diameter² × height. A 12 in Sonotube 4 ft deep holds 0.785 × 1² × 4 = 3.14 ft³; with 10% extra that is 3.46 ft³, or 6 bags of 80 lb (8 bags of 60 lb). In metric, a 300 mm tube 1.2 m deep needs 0.085 m³.

Inputs

Results update as you type.

Tube
in
ft
Allowance
%
Cylinder elevationØ 12 in4 ftmyconstructioncalculator.com
Diagram updates as you type.

Results

Check the working before you order.

Concrete to order
0.13yd³
In cubic feet3.46 ft³
80 lb bags6 bags
60 lb bags8 bags
Price This optional: add your own prices

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Working
  1. Volume per tube = π/4 × D² × H = 0.7854 × (12.0 in = 1.000 ft)² × 4.00 ft = 3.142 ft³
  2. × 1 tubes × 1.10 = 3.46 ft³ = 0.128 yd³
  3. 80 lb bags = ⌈3.46 ÷ 0.60⌉ = 6; 60 lb bags = ⌈3.46 ÷ 0.45⌉ = 8
Results are estimates for planning and material ordering only. They are not a substitute for structural design or approval by a qualified engineer. Read the full disclaimer.
Formula


Volume per tube = π/4 × D² × H
Total           = Volume per tube × number of tubes × (1 + wastage %)
80 lb bags      = ⌈ Total (ft³) ÷ 0.60 ⌉      60 lb bags = ⌈ Total ÷ 0.45 ⌉


Convert the diameter to feet (or metres) before squaring it: 12 in = 1 ft.


Worked Example


One 12 in tube, 4 ft deep, 10% wastage:


    

  1. Volume = 0.7854 × 1.0² × 4 = 3.14 ft³
    2. 

  2. With 10% = 3.46 ft³ (0.13 yd³)
    3. 

  3. 80 lb bags = ⌈3.46 ÷ 0.60⌉ = 6 bags; 60 lb bags = ⌈3.46 ÷ 0.45⌉ = 8 bags
    4. 



Volume and Bags by Tube Diameter






Tube diameter
ft³ per foot of depth
80 lb bags for a 4 ft tube (no wastage)






6 in
0.196
2




8 in
0.349
3




10 in
0.545
4




12 in
0.785
6




14 in
1.069
8




16 in
1.396
10




18 in
1.767
12




24 in
3.142
21






Assumptions


    

  • Nominal inside diameter of the tube; height is the full concrete depth in the tube.
    • 

  • Bag yields: 80 lb = 0.60 ft³, 60 lb = 0.45 ft³, 25 kg ≈ 0.0117 m³.
    • 

  • For many tubes, compare the total with a ready-mix delivery: see the concrete bag calculator.
    • 



Frequently Asked Questions
How many bags of concrete for a 12 inch Sonotube?
About 0.785 ft³ per foot of depth, so a 4 ft tube needs 3.14 ft³: 6 bags of 80 lb or 7 bags of 60 lb before wastage. With 10% extra, plan on 6 × 80 lb or 8 × 60 lb.
How many bags of concrete for an 8 inch tube?
An 8 in tube holds 0.349 ft³ per foot. A 4 ft tube needs 1.40 ft³: 3 bags of 80 lb.
Does the bell or footing at the bottom count?
No. If the tube sits on a flared footing or bell, calculate that separately and add it. Belled footings often hold more concrete than the tube itself.
Should I fill the tube in one go?
Yes, place and consolidate in lifts within one pour to avoid cold joints, rodding or vibrating each lift.
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