TAHA Engineering Toolsby TAHA Knowledge Lab

Material Weight

I-Beam Weight Calculator

Theoretical weight per metre and total weight of a parallel-flange I-beam from its dimensions, including the root radius.

Inputs

I-beam cross-section: a deep web with two narrower parallel flanges, with dimensions h, b, tw, tf and the root radius r marked.bhtftwr — root radius
I-beam cross-section with parallel flanges: depth h, flange width b, web thickness tw, flange thickness tf and root radius r. Diagram not to scale.

Density used: 7,850 kg/m³ — nominal value used in steel section mass tables, e.g. EN 10210-2 and EN 10219-2 (7.85 kg/dm³).

The fillet between web and flange of a rolled beam (from the product table). Enter 0 for a beam welded from plates.

Result

Theoretical weight per metre
22.36
Weight per piece
134.16
Total weight
134.16
Cross-section area
28.4841
Density used
7,850
Working
Flanges 2 × b × tf = 1,700 mm² Web (h − 2tf) × tw = 1,024.8 mm² Root fillets (4 − π) × r² = 123.611 mm² Area A = 2,848.41 mm² Weight per metre = A × ρ = 0.00284841 m² × 7,850 kg/m³ = 22.36 kg/m

This I-beam weighs about 22.36 kg/m (theoretical). One 6 m piece weighs 134.16 kg.

Educational estimate — check the assumptions below.

About this calculator

An I-beam (such as IPE or UB sections) is deeper than it is wide, which makes it efficient in bending. This calculator works out the theoretical weight of a parallel-flange I-beam from the dimensions you enter, including the root radius where the web meets the flanges.

Older I-beams with sloping (tapered) flanges, such as IPN and American Standard S-shapes, are not covered: their geometry needs more data than the five dimensions here.

Formula

A = 2 b tf + (h − 2tf) tw + (4 − π) r²    m′ = A × ρ    m = m′ × L

h = overall depth, b = flange width, tw = web thickness, tf = flange thickness, r = root radius, ρ = density, L = length. The formula is the same as for an H-beam; only the proportions differ.

Worked example

A beam 200 mm deep with 100 mm flanges, a 5.6 mm web, 8.5 mm flanges and a 12 mm root radius, in steel:

  • Flanges: 2 × 100 × 8.5 = 1700 mm²; web: (200 − 17) × 5.6 = 1024.8 mm²; fillets: (4 − π) × 12² = 123.6 mm²
  • A = 2848.4 mm² = 28.48 cm² → 22.36 kg/m; a 6 m piece weighs 134.2 kg

A published European section table lists 28.48 cm² and 22.4 kg/m for a beam with exactly these dimensions.

Assumptions and limitations

  • Theoretical (geometric) weight = area × density. Published masses are nominal values; actual bars differ within rolling tolerances.
  • Parallel flanges only. Tapered-flange beams (IPN, S-shapes) are not covered in this version.
  • The root radius comes from the product table. Enter 0 for a welded beam; weld metal is not included.
  • No section list is built in: enter the dimensions from the manufacturer’s table or the product standard.

References

  • EN 10365 — Hot rolled steel channels, I and H sections: dimensions and masses (for comparison with table values).
  • Steel makers’ section tables list h, b, t_w, t_f, r and the nominal mass of each size.