What density does this calculator use?

It uses 7.87 g/cm³, which is the standard density for pure iron and most wrought iron flat bars. Mild steel (which behaves similarly) uses 7.85 g/cm³ — the difference is less than 0.3% for practical purposes.

Can I use imperial units?

Yes. Switch to Imperial mode and enter width and thickness in inches and length in feet. The calculator converts internally and displays weight in both lb and kg.

What is the formula for iron flat bar weight?

Weight = Width × Thickness × Length × Density. In metric: (mm × mm) / 1,000,000 × length_m × 7,870 gives weight in kg. Dimensions must be consistent before multiplying.

Does the grade of iron affect the result?

Slightly. Pure iron is 7.87 g/cm³, cast iron ranges from 7.20–7.50 g/cm³, and mild steel is about 7.85 g/cm³. For wrought iron and most structural flat bars, 7.87 g/cm³ is a reliable estimate.

How do I calculate weight for multiple bars?

Enter your single-bar dimensions, then set the Quantity field to the number of bars. The total weight section will appear automatically.

Iron Flat Bar Weight Calculator

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

Enter width, thickness, and length of an iron flat bar to instantly calculate its weight using iron density (7.87 g/cm³).

Bar Dimensions

Unit System

Width (mm)

Thickness (mm)

Length (m)

Quantity (bars)

Enter dimensions and press Calculate to see weight.

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Summary

Enter width, thickness, and length of an iron flat bar to instantly calculate its weight using iron density (7.87 g/cm³).

How it works

Select your preferred unit system: metric (mm / m) or imperial (in / ft).
Enter the flat bar width in millimeters or inches.
Enter the flat bar thickness in millimeters or inches.
Enter the total length in meters or feet.
Optionally enter a quantity to compute total weight for multiple bars.
The calculator applies Weight = Width × Thickness × Length × 7.87 g/cm³ to produce results in kg and lb.

Use cases

Estimate iron flat bar weight before placing a material order.
Calculate structural dead load for iron bar components.
Determine freight weight for shipping cost estimation.
Compare mass across different flat bar sizes during design.
Quickly verify weight budgets on fabrication projects.
Convert between kg and lb for cross-region specifications.
Check material quantities against a bill of materials.
Plan lifting and handling requirements on the job site.

Frequently Asked Questions

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