What formula is used to calculate square bar weight?

The formula is: Weight = Side² × Length × Density. This gives the volume of a rectangular prism (a square cross-section bar) which is then multiplied by the material density to get mass.

What is the density of carbon steel?

Carbon steel (mild steel) has a density of approximately 7850 kg/m³ (0.284 lb/in³), which is the standard value used in most structural steel calculations.

Can I calculate weight for multiple bars at once?

Yes. Enter the quantity in the Quantity field and the calculator will multiply the single bar weight by that number to give the total weight.

Does this work for 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 a square bar different from a round bar?

A square bar has a square cross-section (Side × Side), while a round bar has a circular cross-section (π/4 × D²). For the same nominal size, a square bar is about 27% heavier than a round bar of the same dimension.

How accurate is this calculator?

Results are accurate to the theoretical weight based on nominal dimensions and standard densities. Actual bar weight may vary slightly due to manufacturing tolerances and surface finish.

Steel Square Bar Weight Calculator

Name: Steel Square Bar Weight Calculator
Availability: InStock
Author: Nham Vu

Enter side length, bar length, and material to instantly calculate the weight of a square bar in kg and lbs.

Bar Dimensions

Side Length

Bar Length

Material

Quantity (bars)

Formula Reference

W = S² × L × ρ

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

Enter dimensions on the left and click Calculate.

Common Material Densities

Material	kg/m³	lb/in³
Carbon Steel	7850	0.284
Stainless 304	7930	0.286
Stainless 316	8000	0.289
Cast Iron	7200	0.260
Copper	8960	0.324
Brass	8500	0.307
Aluminum	2700	0.098
Titanium	4500	0.163

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Summary

Enter side length, bar length, and material to instantly calculate the weight of a square bar in kg and lbs.

How it works

Enter the bar side length in millimeters, inches, or centimeters.
Enter the bar length in meters, feet, or millimeters.
Select the material from the dropdown to apply the correct density.
Optionally enter a quantity 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 steel weight for structural and fabrication projects.
Calculating material costs for machining and manufacturing jobs.
Comparing weights of different metals for product design.
Freight and shipping weight estimates for metal orders.
Checking weight limits on lifting and handling equipment.
Bill of materials (BOM) preparation for construction.
Verifying supplier quotes against theoretical bar weight.
Academic and training exercises in materials engineering.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu