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title: "Flat, Plate & Square Bar Weight Calculator"
description: "Weight of flat bar, sheet, plate or square bar from thickness, width and length ✅ that grade's measured density ⭐ Factor-8 trade rule shown alongside."
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![Flat, Plate & Square Bar Weight Calculator](/images/uploads/6d8dada0-ce42-43d6-8535-a29ebf48fb6e/flat-bar-weight-calculator-plate-and-square-bar-stack-1920x1080.jpg)

Weight

# Flat, Plate & Square Bar Weight Calculator

Calculate the weight of flat bar, sheet, plate or square bar from thickness, width, length and grade — square bar is simply width = thickness. A real GET form: computes correctly with JavaScript off.

   Cross-section Quantity

 Thickness  mm

 Width  mm

 Square bar: set width = thickness.

 Length  mm

 1 000 mm = 1 m

   Material Steel grade (optional — search by number or designation)  Leave blank to use a generic class estimate instead.

Sourced 7.85 **g/cm³**

1.0038 — Werkstoffnummer catalogue

 Material class (fallback — used only when no grade above is chosen) Generic (no grade selected)Steel (generic) — 7.85 g/cm³Stainless steel, austenitic (generic) — 7.9 g/cm³Non-ferrous (trade conversion)Titanium (commercially pure) — 4.51 g/cm³Aluminium (generic) — 2.7 g/cm³Copper (generic) — 8.93 g/cm³Brass CuZn40 (60/40, generic) — 8.52 g/cm³ Generic values are class averages, never a substitute for a grade's own measured density.

  Calculate [Reset](/calculators/flat-bar-weight.md "Reset the calculator to its default values") Recalculates on submit — the same value renders with JavaScript off.

### Result

 Valid range

Weight per piece**3.925 kg**

Weight per metre**3.925 kg**

Total weight (× qty)**3.925 kg**

**Factor-8 trade rule (assumes 8.00 g/cm³): 4 kg total — +1.911 % vs the exact result above.**

**m** = t × w × L × ρ × 10⁻⁶

Exact cuboid volume × the density shown above — never the Factor-8 shortcut.

**Download as PDF** Result sheet · A4 Run a calculation first — then the sheet is ready to download.

Calculated on SteelEquivalents.com — send us the figures for a quotation.

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## Flat & square bar weight — frequently asked

  How do I calculate a square bar with this form?

Enter the same value for width and thickness — a square bar is the width = thickness special case of the rectangular cross-section.

  What is the Factor-8 rule shown under the result?

A trade shortcut: 8.0 kg per m² per mm of thickness, which silently assumes a density of 8.00 g/cm³. We show it with its delta from the exact result — we never use it as the answer.

  Does the result change when I pick a grade instead of a material class?

Yes — density varies by grade. The material class value is a generic average, only used as a fallback when no specific grade is chosen.