Concrete Column Calculator
A 12 inch round column, 4 feet tall, is 0.12 cubic yards and 6 bags of 80 lb concrete.
Last updated . Weight starts at 2,400 kg/m³, about 2.02 short tons per cubic yard. An 80 lb bag yields 0.60 ft³. No prices.
Count a round or square column, including the common sonotube diameters. Results are cubic yards, cubic feet, cubic meters, tonnes, short tons, and premix bags.
A rectangular footing is the footing calculator. Bag yields are the bag calculator. Bar weight is the rebar calculator.
Column or sonotube
The size is the inside diameter you pour. Check the tube if the label is the outside. A square column ignores this menu.
Yields are the ones on the bag calculator. 25 kg and 50 kg are a mass scale of the 80 lb yield, not a quoted product. Weight uses 2400 kg/m³.
Results
How a column is counted
A round column is the area of a circle times the height: π × radius × radius × height. A 12 inch tube has a 6 inch radius. Four feet of that tube is 3.14 cubic feet, 0.12 cubic yards, and 0.09 cubic meters. A square column is side × side × height. Twelve inches square and 4 feet tall is 4.00 cubic feet.
The sonotube menu writes the diameter in inches. That diameter is the concrete, the inside of the form. Weight is the volume times 2,400 kg/m³. That density is a planning default, not a mix design. Bags use the yields already on the bag calculator: 0.60 ft³ for 80 lb, 0.45 ft³ for 60 lb, 0.30 ft³ for 40 lb, and 0.01171 m³ and 0.02341 m³ for the 25 kg and 50 kg scale.
Sonotube at 4 feet, one column
Each row is one round column, 4 feet tall, 80 lb bags at 0.60 ft³. Switch the menu to see the same line on the form.
| Tube | Volume | 80 lb bags |
|---|---|---|
| 8 in | 0.05 yd³ · 1.40 ft³ | 3 |
| 10 in | 0.08 yd³ · 2.18 ft³ | 4 |
| 12 in | 0.12 yd³ · 3.14 ft³ | 6 |
| 14 in | 0.16 yd³ · 4.28 ft³ | 8 |
| 16 in | 0.21 yd³ · 5.59 ft³ | 10 |
| 18 in | 0.26 yd³ · 7.07 ft³ | 12 |
| 24 in | 0.47 yd³ · 12.57 ft³ | 21 |
Worked example
Leave the shape on round, the tube on 12 in, the height at 4 ft, the count at 1, and the bag on 80 lb. One column reads 0.12 yd³ · 3.14 ft³ · 0.09 m³. All columns read the same, because the count is 1. Weight reads 0.21 tonnes · 0.24 short tons. Bags for one pour read 6. Bags with each column rounded up also read 6.
Frequently asked questions
How much concrete is in a 12 inch sonotube 4 feet tall?
Leave the shape on round, the tube on 12 in, the height at 4 ft, and the count at 1. One column reads 0.12 yd³, 3.14 ft³, and 0.09 m³. At 2,400 kg/m³ the weight is 0.21 tonnes and 0.24 short tons. The diameter is the inside of the tube.
How many 80 lb bags does that column need?
An 80 lb bag yields 0.60 ft³, the same figure as the bag calculator. 3.14 ÷ 0.60 = 5.24, which rounds up to 6 bags. Bags for one pour and bags with each column rounded up both read 6, because there is one column. A 60 lb bag at 0.45 ft³ is 7 bags.
How much concrete for four of those columns?
Set the count to 4. All columns read 0.47 yd³, 12.57 ft³, and 0.36 m³. Weight is 0.85 tonnes and 0.94 short tons. One pour is 21 bags of 80 lb mix. Rounding each column up to 6 bags and buying four of those orders is 24 bags. The separate order is higher because each column is rounded up.
How much is a 12 inch square column?
Switch the shape to square and set the side to 12 in, still 4 ft tall and one column. The volume reads 0.15 yd³, 4.00 ft³, and 0.11 m³. That is 7 bags of 80 lb mix. A square 12 inch column holds more than the 12 inch round tube, which is 3.14 ft³.
How much concrete is in the other sonotube sizes?
At 4 ft and one column, 80 lb bags: 8 in is 0.05 yd³ and 3 bags, 10 in is 0.08 yd³ and 4 bags, 14 in is 0.16 yd³ and 8 bags, 16 in is 0.21 yd³ and 10 bags, 18 in is 0.26 yd³ and 12 bags, and 24 in is 0.47 yd³ and 21 bags. The menu fills the diameter. Choose custom if the tube is another size.
Is 12 inches the inside of the tube?
Enter the inside diameter, because that is the concrete. A tube sold as 12 inch is entered as 12 unless the label is the outside. This page does not add a wall thickness. It is a quantity tool, not a structural design.
Is this the same as a footing?
No. The footing calculator is a rectangular prism, length times width times depth. This page is a round or square column. A spread footing under the column stays on the footing page. Rebar in the pier is the rebar calculator. Premix yields are the bag calculator.