Aluminium flat bar weight calculator
Rectangular bar to any width, thickness and cut length — per piece and for the batch. Handy for stiffeners, frames and edge trim.
Bar dimensions
Material
Multiplied out in metres: width × thickness × length × density. All three dimensions are converted from mm before multiplying.
A (m²) = (w / 1000) × (t / 1000)W (kg) = A × (L / 1000) × ρ
| Common size (mm) | kg per metre (5xxx) |
|---|---|
| 25 × 3 | 0.201 |
| 40 × 5 | 0.536 |
| 50 × 5 | 0.670 |
| 80 × 8 | 1.715 |
| 100 × 10 | 2.680 |
| 150 × 12 | 4.824 |
- Cut length is usually 6,000 mm for European mills, 3,000 or 4,000 mm for container-friendly shipping.
- Flat bar under 3 mm thick is normally supplied as slit coil strip rather than cut bar.
- For long stiffeners, ask for the bar in the mill’s running length and cut on site — it is cheaper than cut-to-length.
People also ask
Is flat bar the same as plate strip?
Effectively yes. A flat bar under about 6 mm thick is usually slit from coil; over that it is sawn or sheared from plate. The weight maths is identical.
What tolerance applies to flat bar?
Width and thickness follow EN 754 / ASTM B221 for extruded bar, or EN 485 for sheared strip. Cut length is normally ±2 mm, tighter on request.
Which alloy for flat bar used on a boat?
5083 or 5086 for anything welded to the hull; 6061 T6 for non-welded brackets and fittings where stiffness matters more than corrosion resistance.
Why use 6061 rather than 5083 for bar?
6061 extrudes well and is stronger in T6, so it suits machined brackets. It is not usually welded into the hull — the heat-affected zone loses strength.
Can I get the bar in 5xxx with a mill certificate?
Yes. Bar and strip ship with a 3.1 mill certificate on request. See certifications.
Need plate to match these numbers?
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