# Sonotube Concrete Calculator

Diameter in inches, height in feet, straight to bags per tube.

- Page: https://jianzhujisuan.com/en/sonotube-concrete
- Category: Concrete (https://jianzhujisuan.com/en/c/concrete)
- Chinese version: https://jianzhujisuan.com/zh/sonotube-concrete.md
- Data checked: 2026-10-25

## Quick result

With the default inputs (Tube diameter 12 in, Pour height 4 ft, Number of tubes 4 pcs, Waste 10%, Bag size 80 lb bag (0.60 ft³ each)): **Total concrete 0.51 yd³**

## Inputs

| Parameter | Type | Default | Unit | Note |
|---|---|---|---|---|
| Tube diameter | number | 12 | in |  |
| Pour height | number | 4 | ft |  |
| Number of tubes | number | 4 | pcs |  |
| Waste | number | 10 | % |  |
| Bag size | select | 80 lb bag (0.60 ft³ each) | — |  |

## Formula

- **Area = π × (D/24)²**: D in inches, D/24 is the radius in feet
- **Volume per tube = area × pour height**: height in feet
- **Total = per tube × count × (1 + waste)**: 
- **Cubic yards = ft³ ÷ 27**: 

## Worked example

Six 12 in tubes at 4 ft each with 10% waste: area = π × (12/24)² = 0.785 ft², so 3.14 ft³ per tube, 18.85 ft³ total, 20.7 ft³ with waste = 0.77 cubic yards or 35 bags of 80 lb, which is 6 bags per tube.

## Questions

### How much more concrete does a 12 in tube take than an 8 in?

More than double. Volume scales with the square of diameter: an 8 in tube is 0.349 ft² and a 12 in is 0.785 ft², so at the same height the 12 in takes 2.25 times the concrete. Do not oversize by feel - 8 in carries a deck post, and 12 in is for loaded porch columns or light pole bases.

### How deep and how long should the tube be?

In cold regions footings go below frost depth - commonly 36 to 48 in, and local codes vary. Warmer areas are fine at 24 to 36 in. Leave the tube standing above grade: about 6 in above a slab creates a moisture break, while on soil or gravel keep the top just proud of grade so water runs away rather than in.

### Do I leave the Sonotube in the ground?

Fibre tubes are normally left in place - they do not rot in a way that affects the footing. If your inspector wants them off, or you want concrete against soil, strip them within about 24 hours of set while they still peel easily. Left for days they harden and take the arris off the concrete with them.

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