W 12X30 vs H-300x150x7.5x12
W 12X30 is an W section from the American AISC Shapes Database; H-300x150x7.5x12 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 706.28 cm³ against 702 cm³ of plastic modulus, a difference of 0.6%. W 12X30 is the lighter of the two at 44.6 kg/m against 46.2 kg/m, a saving of 3.5% on steel weight. W 12X30 is deeper, 312.4 mm against 306 mm, which matters where the floor zone is tight.
| Property | W 12X30 W | H-300x150x7.5x12 MB & MC | Difference |
|---|---|---|---|
| Mass | 44.6 kg/m | 46.2 kg/m | -3.5% |
| Depth | 312.4 mm | 306 mm | +2.1% |
| Width | 165.6 mm | 151 mm | +9.7% |
| Web thickness | 6.6 mm | 7.5 mm | -12.0% |
| Flange thickness | 11.2 mm | 12 mm | -6.7% |
| Area | 56.7 cm² | 58.8 cm² | -3.6% |
| Second moment, major (Iy) | 9,906 cm⁴ | 9,514 cm⁴ | +4.1% |
| Plastic modulus, major (Wpl,y) | 706.28 cm³ | 702 cm³ | +0.6% |
| Elastic modulus, major (Wel,y) | 632.54 cm³ | 622 cm³ | +1.7% |
| Second moment, minor (Iz) | 844.9 cm⁴ | 691 cm⁴ | +22.3% |
| Plastic modulus, minor (Wpl,z) | 156.66 cm³ | 142 cm³ | +10.3% |
| Radius of gyration, minor (iz) | 3.86 cm | 3.43 cm | +12.5% |
| Torsion constant (It) | 19.02 cm⁴ | 24.9 cm⁴ | -23.6% |
W 12X30 to AISC Shapes Database v16.0; H-300x150x7.5x12 to Continental Steel. Difference is expressed relative to H-300x150x7.5x12.
How to choose between them
On stiffness, W 12X30 has the larger second moment of area: 9,906 cm⁴ against 9,514 cm⁴, a difference of 4.1%. This matters more often than the strength comparison, because on normal floor spans deflection rather than bending capacity sets the beam size - so if the two are close on modulus but apart on inertia, the stiffer one is usually the better answer even when it is not the stronger one.
Measured as bending capacity per kilogram of steel, W 12X30 is the more efficient section: 15.8 against 15.2 cm³ per kg/m, 4.2% better. Over a floor of repeated beams that difference is real tonnage, though it is often outweighed by whichever section the fabricator can actually source.
The two diverge much more about the minor axis: W 12X30 has 156.66 cm³ of minor-axis plastic modulus against 142 cm³, 10.3% more. If the member sees any minor-axis bending, or if it is unrestrained over a long length and lateral-torsional buckling governs, that gap decides the comparison even though the major-axis numbers looked equivalent.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. W sections are specified to AISC Shapes Database v16.0 and MB & MC to Continental Steel; the steel grades, tolerances and available lengths differ, connection details and bolt gauges are set out differently, and the two are rarely both stocked in the same market. Check availability before changing a section on a drawing to save 3.5% weight.
In short, W 12X30 is the stronger section and W 12X30 is the lighter one; where those are the same section, it is the clear choice, and where they are not, decide on whether your design is governed by capacity or by tonnage.