Concrete tools

Column Concrete Calculator — Square, Rectangular & Circular

Enter the actual concrete height and cross-section for one or more identical columns to estimate volume and complete bag quantities.

Rectangular & circular columns
Metric & imperial inputs
Final-project bag rounding

Column geometry

Enter the actual column dimensions

Column cross-section

Measurement system

Column heightftUse the actual concrete height from the project design.Column widthinColumn depthinIdentical columnsqty

Quantity only — BuildNumbers does not choose structural column dimensions, reinforcement, concrete strength, or load capacity.

Extra allowance%Adjust for placement loss, form tolerances, and field variation.Bag sizeApproximate manufacturer-published yields; verify your product.

Optional price per 80 lb bag$Uses the supplier price you enter for the current 80 lb bag. No live prices are fetched.Currency labellabelDisplay only. BuildNumbers does not convert currencies or exchange rates.

This device

Saved estimates

Save an estimate to keep it here. Data stays in this browser.

Transparent by design

Column concrete formulas

BuildNumbers first calculates the cross-sectional area, then multiplies by the entered concrete height. Identical columns are combined before the extra allowance and final bag rounding are applied.

Rectangular sectionA = width × depthCircular sectionA = π × (diameter ÷ 2)²Per columnV = A × heightOrder volumeV_order = (V × quantity) × (1 + allowance ÷ 100)

The result is a material quantity only. Use dimensions and concrete requirements from the project plans or another qualified design source.

Worked example

Three 12 in × 12 in × 10 ft columns

This controlled quantity example demonstrates total-project allowance and bag rounding. It is not a recommended structural column size.

01
One column1 ft × 1 ft × 10 ft = 10 ft³
02
Three columns10 × 3 = 30 ft³
03
Add 10%30 × 1.10 = 33 ft³
04
80 lb bags33 ÷ 0.60 = 55

Verified result1.222 yd³ and 55 × 80 lb bags at 10% allowance

Confirm the actual structural dimensions, concrete specification, and selected product yield before ordering.

Common questions

Column concrete calculator FAQ

Material quantity without hidden structural assumptions.

How do I calculate concrete for a rectangular column?

Multiply the column width by its depth to get cross-sectional area, then multiply by the concrete height. For multiple identical columns, multiply that volume by the quantity before applying your extra allowance.

How do I calculate concrete for a circular column?

Use the circular cross-section area π × radius squared, then multiply by the concrete height. BuildNumbers converts the entered diameter to radius internally and totals all identical columns before package rounding.

Does this calculator choose column size or reinforcement?

No. It only calculates material quantity from dimensions you provide. Structural dimensions, reinforcement, concrete strength, load capacity, connections, and code compliance must come from the project design and applicable requirements.

How are concrete bags rounded?

The calculator totals all identical columns, applies the selected extra allowance, divides by the selected manufacturer-published bag yield, and rounds the final purchase quantity up once.

Can I switch between metric and imperial measurements?

Yes. Height uses feet or meters while cross-section dimensions use inches or centimeters. Switching systems converts the dimensions already entered.

Continue planning

Use the right concrete geometry for the next estimate.

GuideHow Much Concrete for Columns?Rectangular & circular formulas LiveFooting ConcreteRectangular foundations