Flat Bar Weight
A steel 50×10 mm flat bar weighs about 3.92 kg/m (2.64 lb/ft). Change the size, material or length below for an exact figure.
Common flat bar sizes — steel weight
| Size (mm) | kg/m | lb/ft |
|---|---|---|
| 20×3 mm | 0.471 | 0.316 |
| 25×3 mm | 0.589 | 0.396 |
| 25×6 mm | 1.18 | 0.791 |
| 40×6 mm | 1.88 | 1.27 |
| 50×6 mm | 2.36 | 1.58 |
| 50×10 mm | 3.92 | 2.64 |
| 60×10 mm | 4.71 | 3.16 |
| 80×10 mm | 6.28 | 4.22 |
| 100×10 mm | 7.85 | 5.27 |
| 100×12 mm | 9.42 | 6.33 |
Carbon steel, ρ = 7.85 g/cm³. Other materials scale linearly with density — use the selector above.
How flat bar weight is calculated
Weight comes straight from geometry and density: work out the cross-section area of the profile, then multiply by length and the material's density. For flat bar the cross-section follows flat bar geometry, and mass per metre is that area times density. Carbon steel is 7.85 g/cm³; that single number is why a steel part weighs almost three times an identical aluminium one (2.70 g/cm³).
The quick-reference table above is calculated for carbon steel. For any other material, use the calculator's material selector — the weight scales linearly with density, so stainless (8.0) comes out about 2% heavier than steel, and aluminium about 66% lighter, for the same dimensions.
Per-metre vs. total weight
Bar, tube and section stock is usually quoted in kg per metre (or lb per foot). The calculator shows both the per-metre rate and the total for the cut length you enter — handy for working out shipping weight or checking a delivery against the packing list.
Why calculated beats a printed chart
Stock charts only list round-number sizes in one material. Real jobs use odd cut lengths, mixed materials and non-standard sections. Computing the weight from dimensions means you get the exact figure for your piece — not the nearest row on a wall chart.
References
- Densities: standard handbook values (ASM Metals Reference Book; matweb typical values). Mill stock varies a few percent with alloy and tolerance.
- Cross-section relations: standard mensuration formulas per profile geometry.
Last reviewed: 2026-07 · Calculation method & assumptions