What formula is used to calculate flat bar weight?

The formula is: Weight = Width × Thickness × Length × Density. This computes the rectangular volume of the bar and multiplies by the material density to get mass.

How much does a steel flat bar weigh?

A 50 × 6 mm carbon steel flat bar (density 7850 kg/m³) weighs about 2.36 kg per meter — 0.05 × 0.006 × 1 × 7850. Multiply by your length to get the total weight.

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 total weight.

Does this work for metric and imperial units?

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

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.

What is the difference between a flat bar and a plate?

A flat bar is a long rectangular section with a defined width and thickness, typically narrower than a plate. The weight formula is identical — width × thickness × length × density.

Steel Flat Bar Weight Calculator

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

Enter width, thickness, and length of a flat bar, choose material, and get the weight in kg and lbs instantly.

Bar Dimensions

Width

Thickness

Length

Material

Quantity (bars)

Formula Reference

W = Width × Thickness × Length × ρ

Where W = width (m), T = thickness (m), L = length (m), ρ = density (kg/m³). Result is weight in 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 width, thickness, and length of a flat bar, choose material, and get the weight in kg and lbs instantly.

How it works

Enter the bar width in millimeters or inches.
Enter the bar thickness in millimeters or inches.
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 = W × T × L × ρ and displays the result in kg and lbs.
Use the Copy button to copy the result to your clipboard.

Use cases

Estimating steel weight for structural engineering and fabrication projects.
Calculating material costs for machining, welding, and metalwork.
Comparing weights of different metals for product design.
Freight and shipping weight estimates for metal orders.
Checking weight limits on lifting equipment.
Bill of materials (BOM) preparation for manufacturing.

Frequently Asked Questions

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