Formulas used
Round bar: kg/m = d² / 162.28 (d in mm)
Square bar: kg/m = (d² × 7850) / 1,000,000
Flat plate: kg/m = (w × t × 7850) / 1,000,000
The 162.28 constant comes from π × 7850 ÷ 4 ÷ 1,000,000 ≈ 0.006165 kg per mm² per metre, which is 1 / 162.28. Round it to 162 for a quick mental estimate; this calculator uses the precise value.
Common rebar weights
| Diameter | kg / m | Pieces per tonne (12m) |
|---|---|---|
| 8 mm | 0.395 | ~211 |
| 10 mm | 0.617 | ~135 |
| 12 mm | 0.889 | ~94 |
| 16 mm | 1.580 | ~53 |
| 20 mm | 2.470 | ~34 |
| 25 mm | 3.858 | ~22 |
| 32 mm | 6.321 | ~13 |
FAQ
Does this work for TMT bar?
Yes — TMT (thermo-mechanically treated) bars use the same nominal density. Actual measured weight may differ by ±3% per IS 1786 tolerances, so order with a small buffer.
What about angle, channel or I-beam?
Those rolled sections have specified unit weights in IS 808 / SP 6 tables — use the manufacturer's catalogue or steel tables rather than computing from raw dimensions, since web and flange thicknesses vary.