Concrete column calculator
Size a solid round pour, then multiply it by the number of forms.
Calculating example…
Estimates only · see assumptions below
Your material estimate
Example estimate— yd³
- Cubic feet
- —
- Cubic meters
- —
Shape assumption. Solid circular cylinders, identical sizes. Use the inside diameter. No hollow core, flared footing or separate pad is included.
Or use premix bags
Choose one row. Whole bags rounded up after waste.
| Bag size | Typical yield | Bags |
|---|---|---|
| 80 lb | 0.60 ft³ | — |
| 60 lb | 0.45 ft³ | — |
| 40 lb | 0.30 ft³ | — |
Typical values; use the yield on the bag label. These are concrete premix bags, not plain cement.
Volume × your $/yd³. Excludes tax, delivery, short-load fees, labor and equipment. Truck capacity and minimum orders vary.
Enter positive dimensions to see a material estimate.
Estimates only. Displayed volumes use 3 decimals; calculations and bag rounding use unrounded values. Confirm supplier increments before ordering. Not construction, commercial or tax advice.
How to calculate
- Measure the shape shown above. Use the unit labels beside each field.
- Choose a waste allowance from 0–30%. The example starts at 10%.
- Read the waste-adjusted volume or choose one bag size. Add a material price if you have a quote.
- Copy or print the estimate, then verify the mix yield and order increments with your supplier.
The formula
Volume (ft³) = π × (inside diameter in feet ÷ 2)² × pour height in feet × column count. Divide inch dimensions by 12 first. Divide ft³ by 27 for yd³.
Waste-adjusted volume = measured volume × (1 + waste percent ÷ 100). One cubic foot is 0.028316846592 cubic meters. Bag counts round up once; displayed volumes round to three decimals.
Worked example
Two 12 in diameter columns, each 4 ft high: π × (1 ÷ 2)² × 4 × 2 = 6.283185 ft³. With 10% waste: 0.255982 yd³, or 12 typical 80 lb bags.
Ready-mix material cost = waste-adjusted cubic yards × your price per cubic yard. A bag cost, when entered, is whole bags × price per bag. Neither cost includes delivery, tax, short-load fees, labor or equipment.
Geometry estimates material only. It does not select concrete strength, reinforcement, dimensions or a construction method.
Frequently asked questions
Do I use the inside or outside tube diameter?
Use the inside diameter of the space that will hold concrete. The tube wall is not part of the pour.
Can I calculate several columns at once?
Yes, when all columns have the same diameter and pour height. Enter a whole-number count. Calculate different sizes separately.
Does it include the footing below the tube?
No. The calculation includes only the straight cylinder. Use the footing tool for rectangular bases and account for overlaps.
Can it calculate hollow pipes?
No. This tool assumes a solid pour. A hollow cylinder requires subtracting the interior void volume.
Why does a wider form use much more concrete?
Diameter is squared. Doubling the diameter multiplies the volume by four when height is unchanged.
Does it recommend a structural column size?
No. Diameter and height are your measurements. Structural design, reinforcement and tube selection require qualified advice.