Concrete Column Calculator — Round & Rectangular Columns
Enter the column shape, dimensions, height and number of columns to calculate the total concrete volume in cubic yards, cubic metres and 80 lb bag counts.
Column shape
Unit system
in
ft
0.178 m³ · 6.28 ft³
0.178 m³
per column- 1
Radius
0.3048 m ÷ 2 = 0.1524 - 2
Cross-section area
π × 0.1524² = 0.07297Circle area = π × r² - 3
Volume per column
0.07297 m² × 2.438 m = 0.17792 - 4
Total in cubic yards
0.1779 m³ ÷ 0.7646 = 0.233
How does this calculator work?
Round column: V = π × r² × h. Rectangular: V = W × D × H. Multiply by the number of columns for the total. Convert ft³ to yd³ (÷ 27) and divide by 0.022 yd³ per 80 lb bag for the bag count. Add 5–10% for waste when ordering.
Formula
How this is calculated
A cylindrical (round) column has a circular cross-section and its volume is π × r² × h, where r is the radius (half the diameter) and h is the height. A square or rectangular column is a cuboid with volume = width × depth × height. All inputs are converted to metres before multiplying, and the result is then expressed in cubic metres, cubic yards and cubic feet for convenience.
For multiple columns the per-column volume is multiplied by the count. The bag estimate uses a published yield of 0.60 ft³ per 80 lb bag of pre-mixed concrete (Quikrete / Sakrete data). These are dry mix bags — for large pours you will typically order ready-mix concrete by the cubic yard instead.
Add 5–10% extra when ordering to account for spillage and the fact that form surfaces are rarely perfectly smooth. This calculator covers only the concrete volume; rebar (reinforcement) quantities depend on the structural design and are not included here.
Frequently asked questions
Use V = π × r² × h. For a 12-inch diameter (r = 0.5 ft) and 8 ft tall column: V = π × 0.25 × 8 ≈ 6.28 ft³ ≈ 0.233 yd³. At 0.022 yd³ per 80 lb bag you need roughly 11 bags.
Yes — add 5–10% for spillage, imperfect forms and settling. Columns with rebar will also displace some volume, though the effect is small and typically ignored in estimating.
Bags are practical for small jobs (a few columns). For more than about 1 yd³ (≈ 27 ft³), ready-mix concrete delivered by truck is faster and cheaper per yard.
Also known as
TG we-Calculate Editorial Team. (2026). Concrete Column Calculator — Round & Rectangular Columns [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/concrete-column-calculator
TG we-Calculate Editorial Team. "Concrete Column Calculator — Round & Rectangular Columns." TG we-Calculate. 2026. https://we-calculate.com/calculator/concrete-column-calculator.
TG we-Calculate Editorial Team, "Concrete Column Calculator — Round & Rectangular Columns," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/concrete-column-calculator
@misc{wecalculate_concrete_column_calculator, title = {Concrete Column Calculator — Round & Rectangular Columns}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/concrete-column-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?