What formula is used to calculate hexagon bar weight?

The cross-section area of a regular hexagon is A = (√3 / 2) × AF², where AF is the across-flats dimension in meters. Weight is then W = A × L × ρ, where L is length in meters and ρ is density in kg/m³.

What does "across-flats" (AF) mean?

Across-flats (AF) is the distance measured between two parallel, opposite flat faces of the hexagon. It is the standard specification for hex bar size and differs from across-corners (vertex to vertex).

What is the density of stainless steel 304?

Grade 304 (and 304L) has a standard density of 7930 kg/m³ (0.286 lb/in³). This is the most common austenitic stainless steel grade.

How does 316 differ from 304 in weight?

Grade 316 has a density of 8000 kg/m³ versus 7930 kg/m³ for 304 — roughly 0.9% heavier for the same dimensions. The primary practical difference is corrosion resistance, not weight.

Can I calculate weight for multiple bars?

Yes. Enter the quantity in the Quantity field and the calculator multiplies the single-bar weight by that number to return the total weight.

Does the tool support imperial units?

Yes. You can enter the across-flats in mm, cm, or inches, and bar length in m, mm, ft, or inches. Internal calculations are performed in SI units and results are shown in both kg and lbs.

How accurate are these results?

Results reflect the theoretical weight based on nominal dimensions and standard published densities. Actual bar weight may vary by ±1–2% due to manufacturing tolerances, surface condition, and mill certification variations.

What is the difference between a hex bar and a round bar of the same size?

For the same nominal across-flats size, a hex bar has an area of (√3/2) × AF² while a round bar of the same diameter has area (π/4) × D². A hex bar is approximately 82.7% of the weight of a round bar with diameter equal to the AF dimension.

Stainless Steel Hexagon Bar Weight Calculator

Name: Stainless Steel Hexagon Bar Weight Calculator
Availability: InStock
Author: Nham Vu

Select a stainless steel grade, enter the across-flats size and bar length, and instantly get weight in kg and lbs.

Bar Dimensions

Stainless Steel Grade

Across-Flats (AF) — flat face to flat face

Bar Length

Quantity (bars)

Formula Reference

A = (√3 / 2) × AF²
W = A × L × ρ

Where AF = across-flats (m), L = length (m), ρ = density (kg/m³), W = weight (kg).

Select a grade, enter dimensions, and click Calculate.

Grade Density Reference

Grade	Type	kg/m³	lb/in³
304 / 304L	Austenitic	7930	0.286
316	Austenitic	8000	0.289
316L	Austenitic	7990	0.289
321	Austenitic	7920	0.286
347	Austenitic	7960	0.288
430	Ferritic	7700	0.278
410 / 420	Martensitic	7700	0.278
440C	Martensitic	7750	0.280
17-4 PH	Precip. Hard.	7780	0.281
2205 Duplex	Duplex	7805	0.282
2507 Super Duplex	Duplex	7810	0.282

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Summary

Select a stainless steel grade, enter the across-flats size and bar length, and instantly get weight in kg and lbs.

How it works

Select the stainless steel grade from the dropdown — the correct density is applied automatically.
Enter the across-flats (AF) value — the distance between two parallel flat faces of the hex bar.
Select the unit for the across-flats value (mm, cm, or inches).
Enter the bar length and choose its unit (m, mm, ft, or in).
Optionally enter a quantity to calculate the total weight for multiple bars.
Click "Calculate Weight" — the tool applies Area = (√3 / 2) × AF², then W = Area × L × ρ and shows results in kg and lbs.

Use cases

Estimating hex bar stock weight for fabrication and machining projects.
Calculating freight and shipping weight for stainless steel hex bar orders.
Preparing bills of materials for food-processing or marine equipment.
Comparing the weight impact of selecting 304 vs 316 vs duplex grades.
Checking load capacity against lifting equipment rated limits.
Quick weight verification during procurement and purchasing.
Engineering cost estimates for stainless steel structural components.
Supporting quality assurance checks against nominal weight tolerances.

Frequently Asked Questions

Last updated: 2026-06-21 · Reviewed by Nham Vu