What formula is used to calculate aluminum hexagon bar weight?

The formula is: Weight = (√3/2) × AF² × Length × Density. AF (across-flats) and length are converted to meters. The cross-section area of a regular hexagon expressed in terms of across-flats distance is (√3/2) × AF². Multiplying by length gives volume (m³), and multiplying by alloy density (kg/m³) gives weight in kilograms.

What is the across-flats (AF) dimension?

The across-flats (AF) dimension, also called the "width across flats" or "wrench size", is the distance between two parallel flat sides of a hexagonal bar. It is the measurement used on hex bolts, nuts, and hex stock. It differs from the across-corners dimension, which is AF × (2/√3) ≈ AF × 1.155.

What is the density of aluminum used in this calculator?

The default alloy is 6061 at 2700 kg/m³. Pure aluminum (1100) is also 2700 kg/m³. High-strength 7075 is 2810 kg/m³, aircraft-grade 2024 is 2780 kg/m³, and marine-grade 5052 is 2680 kg/m³. You can also enter a custom density for other materials.

Does this calculator support metric and imperial units?

Yes. The across-flats dimension can be entered in mm, cm, or inches. Bar length can be entered in meters, mm, feet, or inches. All values are converted to meters internally before the calculation.

How does hexagon bar weight compare to round bar of the same nominal size?

A hexagon bar is heavier than a round bar of the same nominal (AF) diameter. The hexagon cross-section area is (√3/2) × AF² ≈ 0.866 × AF², whereas the round bar area is (π/4) × D² ≈ 0.785 × D². So a hex bar weighs about 10% more than a round bar of the same nominal size.

Can I calculate the total weight for multiple bars?

Yes. Enter the number of bars in the Quantity field and the calculator will show both the per-bar weight and the total weight for the entire batch.

Aluminum Hexagon Bar Weight Calculator

Enter the across-flats size, bar length, and alloy grade to instantly calculate aluminum hexagon bar weight in kg and lbs.

Bar Dimensions

Across-Flats (AF)

Distance between two parallel flat sides (wrench size).

Bar Length

Aluminum Alloy

Quantity (bars)

Formula Reference

W = (√3/2) × AF² × L × ρ

Where AF = across-flats (m), L = bar length (m), ρ = alloy density (kg/m³), W = weight (kg). Cross-section area = (√3/2) × AF² ≈ 0.866 × AF².

Enter dimensions on the left and click Calculate.

Aluminum Alloy Densities

Alloy	Grade / Use	kg/m³	lb/in³
1100	Pure / Chemical	2700	0.0975
2011	Free-Machining	2830	0.1022
2024	Aircraft / High Strength	2780	0.1004
3003	General Purpose	2730	0.0986
5052	Marine Grade	2680	0.0968
6061	Structural / Most Common	2700	0.0975
6063	Architectural / Extrusion	2700	0.0975
7075	Aerospace / Max Strength	2810	0.1015

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Summary

Enter the across-flats size, bar length, and alloy grade to instantly calculate aluminum hexagon bar weight in kg and lbs.

How it works

Enter the across-flats (AF) dimension of the hexagon bar in millimeters, inches, or centimeters.
Enter the bar length in meters, millimeters, feet, or inches.
Select the aluminum alloy grade from the dropdown.
Optionally enter a quantity for multiple bars.
The calculator applies W = (√3/2) × AF² × L × ρ and shows weight in kg and lbs.
Click Copy to save the result to your clipboard.

Use cases

Estimating aluminum hexagon bar weight for machining and CNC turning stock.
Calculating freight and shipping weight for hex bar stock orders.
Comparing alloy weights to optimize product design for weight savings.
Preparing bill of materials (BOM) for bolt, nut, and fastener manufacturing.
Verifying load limits on lifting and material handling equipment.
Cost estimation for aluminum hex bar purchases priced by weight.
Material planning for valve bodies, fittings, and plumbing components.
Comparing hex bar vs. round bar weight for the same nominal size.

Frequently Asked Questions

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