What formula is used to calculate iron square bar weight?

The formula is: Weight = Side² × Length × Density. The square cross-section area (Side²) is multiplied by the bar length to get volume, then multiplied by the iron density to get mass. For linear weight per meter, the formula is: Weight/m = Side² × Density.

What is the density of cast iron?

Gray cast iron has a density of approximately 7150 kg/m³, while ductile (nodular) iron is around 7100 kg/m³ and white cast iron is around 7700 kg/m³. The exact value varies with alloy composition.

What is the density of wrought iron?

Wrought iron has a density of approximately 7750 kg/m³, slightly lower than carbon steel due to its slag inclusions and lower carbon content.

Does this calculator support metric and imperial units?

Yes. You can enter dimensions in millimeters, centimeters, inches, meters, or feet. Select your preferred unit from the dropdown next to each input field.

How is an iron square bar different from a steel square bar?

Iron bars (especially cast iron) tend to be more brittle than steel and are used in different applications. Their densities are also slightly different — cast iron is typically 7100–7200 kg/m³ versus carbon steel at 7850 kg/m³.

How accurate is this calculator?

Results are accurate to the theoretical weight based on nominal dimensions and standard densities. Actual weight may vary slightly due to manufacturing tolerances and alloy composition differences.

Iron Square Bar Weight Calculator

Enter the side dimension and length of an iron square bar to instantly get its weight in kg and lbs.

Bar Dimensions

Side Length

Bar Length

Iron Grade

Quantity (bars)

Formula Reference

W = S² × L × ρ

Where S = side length (m), L = bar length (m), ρ = density (kg/m³), W = weight (kg).

Linear Weight (kg/m) = S² × ρ

Weight per meter is calculated using side length in meters multiplied by iron grade density.

Enter dimensions on the left and click Calculate.

Iron Grade Densities

Iron Grade	kg/m³	lb/in³
Gray Cast Iron	7150	0.258
Ductile / Nodular Iron	7100	0.257
White Cast Iron	7700	0.278
Malleable Cast Iron	7300	0.264
Wrought Iron	7750	0.280

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Summary

Enter the side dimension and length of an iron square bar to instantly get its weight in kg and lbs.

How it works

Enter the bar side dimension in millimeters, inches, or centimeters.
Enter the bar length in meters, feet, or millimeters.
Select the iron grade from the dropdown to apply the correct density.
Optionally enter a quantity to calculate total weight for multiple bars.
The calculator applies the formula Weight = Side² × Length × Density and displays results in kg and lbs.
Use the Copy button to copy the result to your clipboard.

Use cases

Estimating iron bar weight for structural and fabrication projects.
Calculating material costs for machining and manufacturing jobs.
Freight and shipping weight estimates for iron material orders.
Checking weight limits on lifting and handling equipment.
Bill of materials (BOM) preparation for construction projects.
Verifying supplier quotes against theoretical iron bar weight.
Comparing cast iron and wrought iron weights for design decisions.
Academic and training exercises in materials and civil engineering.

Frequently Asked Questions

Last updated: 2026-09-19 · Reviewed by Nham Vu