The dimensions used
| Diameter | 12 in |
|---|---|
| Height | 4 ft |
| Columns | 1 |
Column
Concrete for a 12 in sonotube, 4 ft tall
A single 12 in diameter round column (sonotube) 4 ft tall. The volume is the circle area π·(diameter/2)² times the height; multiply the bag counts by the number of piers you are pouring.
Concrete needed
0.12cubic yards· 0.089 m³· 3.14 ft³
| Bag size | Bags needed |
|---|---|
| 40 lb | 11 |
| 60 lb | 7 |
| 80 lb | 6 |
| 25 kg | 8 |
| 30 kg | 7 |
Planning estimate, with no waste allowance included. Add 5–10% for spillage and over-excavation, and check the yield printed on your bag. Structural work must follow your local building code and an engineer's specification.
How it is worked out
A round column or sonotube form holds a cylinder of concrete: area π·(diameter/2)² times its height, multiplied by how many you are pouring. Enter the tube's inside diameter — that is the finished column diameter.
That volume — 3.14 ft³ — is divided by 27 to give 0.12 cubic yards, and by each bag's yield to give the bag count. An 80 lb bag of premix yields about 0.60 cubic feet, so this job takes 6 of them; bag counts always round up, because you cannot buy part of a bag.
Ordering ready-mix instead? Suppliers sell by the cubic yard (or cubic metre) and usually have a minimum load and a short-load surcharge — worth a call before you choose between bags and a truck.
Formwork
What is being measured
Nearby
More column examples
Concrete for a 6 in sonotube, 4 ft tall0.03 yd³Concrete for a 6 in sonotube, 6 ft tall0.04 yd³Concrete for a 6 in sonotube, 8 ft tall0.06 yd³Concrete for a 8 in sonotube, 4 ft tall0.05 yd³Concrete for a 8 in sonotube, 6 ft tall0.08 yd³Concrete for a 8 in sonotube, 8 ft tall0.1 yd³Concrete for a 10 in sonotube, 4 ft tall0.08 yd³Concrete for a 10 in sonotube, 6 ft tall0.12 yd³