How many cement bags are needed per m³ of concrete?

For standard concrete (250 kg/m³ mix), you need 5 bags of 50 kg per m³. For structural concrete (300 kg/m³), use 6 bags. This calculator uses the typical dosage for each element type.

Why should I add a wastage percentage?

On-site losses from spillage, unusable mixes and level corrections always occur. Adding 5–10 % to your final order ensures you don't run short of material.

What is the difference between mass concrete and reinforced concrete?

Mass concrete has no steel reinforcement and is used for low-load foundations. Reinforced concrete includes steel bars that provide tensile strength, making it suitable for slabs, columns and beams.

Concrete Column Calculator

Last updated: 2026-05-09

Use the Concrete Column Calculator to get instant, accurate results. Enter your values below.

Inputs

Dimensions

Column width (m) (m)

Column depth (m) (m)

Column height (m) (m)

Quantities & Type

Number of columns

Wastage Allowance (%)

Result

Enter values and press Calculate

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Common Sizes — Click to Fill

	Column width (m) (m)	Column depth (m) (m)	Column height (m) (m)	Number of columns (ud)
Caso 1	0.2 m	0.2 m	1.2 m	2.4 ud
Caso 2	0.21 m	0.21 m	2.1 m	4.2 ud
Caso 3	0.3 m	0.3 m	3.0 m	6.0 ud
Caso 4	0.45 m	0.45 m	4.5 m	9.0 ud
Caso 5	0.75 m	0.75 m	7.5 m	15.0 ud

Popular combinations

Concrete Columns 0.25×0.25m, 2.5m High – 2 Columns Concrete Columns 0.25×0.25m, 3.5m High – 2 Columns Concrete Columns 0.3×0.3m, 2.5m High – 2 Columns Concrete Columns 0.35×0.35m, 2.5m High – 2 Columns Concrete Columns 0.35×0.35m, 3.5m High – 2 Columns Concrete Columns 0.4×0.4m, 2.5m High – 2 Columns Concrete Columns 0.4×0.4m, 3.0m High – 10 Columns Concrete Columns 0.4×0.4m, 4.0m High – 10 Columns

What is a Concrete Column?

A concrete column is a vertical structural element that transfers compressive loads from beams and slabs down to the foundations. Columns can be square, rectangular, circular or L-shaped. This calculator estimates concrete volume, steel reinforcement and formwork for rectangular columns.

Volume and Steel Calculation

Volume = Width × Depth × Height × Number of columns

Typical residential columns: 250-400mm square. Commercial columns: 400-800mm. Steel reinforcement typically runs 100-160 kg/m³ for columns.

Worked Example

4 columns each 0.40m × 0.40m, 3m high:

Volume per column = 0.40 × 0.40 × 3 = 0.48 m³
Total concrete = 0.48 × 4 = 1.92 m³
Cement = 1.92 × 7 ≈ 14 bags
Steel = 1.92 × 120 kg/m³ ≈ 230 kg
Formwork = 4 × perimeter × height × columns

Common Mistakes

Insufficient longitudinal reinforcement ratio (minimum 1%)
Wrong tie spacing — too wide causes buckling of main bars
Poor concrete consolidation — honeycombing in heavily reinforced columns
Misaligned starter bars from footing

Standards

Calculated per EN 1992-1-1.

Written and reviewed by the CalcToWork editorial team. Last updated: 2026-05-09.