JIS/GB beam sizes vs European sections

A Japanese or Chinese H-beam can look very similar to a European HE profile on a drawing. That does not make the section names interchangeable.

The safest approach is to treat a JIS/GB-to-EN comparison as a dimensional and structural-property screening exercise, not as a grade or section equivalence statement.

The three systems use different section standards

For the dimensional families discussed here:

• JIS G 3192:2024 specifies dimensions, shape, mass and tolerances for hot-rolled steel sections in Japan.
• GB/T 11263-2024 is the current Chinese standard for hot-rolled H and cut-T sections.
• EN 10365:2026 specifies nominal dimensions and masses for European hot-rolled channels and I/H sections, including IPE, HE, HL, HD, HP, UB and UC series.

These standards define different section series and tables. A designation that looks similar numerically does not prove that the geometry or structural properties are the same.

Start by decoding the actual geometry

A JIS or GB H-section is commonly described using dimensions such as:

H × B × tw × tf

where:

• H = overall depth;
• B = flange width;
• tw = web thickness;
• tf = flange thickness.

European HE/IPE designations work differently. A designation such as HEB 300 identifies a standardized series and nominal size; the full dimensions have to be taken from the applicable section table.

See How to read beam dimensions: h, b, tw, tf and root radius.

Do not infer dimensions from an incomplete commercial description

A historical MetalMate discussion used the description “JIS H300×300×129”. The number 129 appears to be a mass-per-metre description, but that alone is not enough to infer the web and flange thickness.

This is exactly the kind of enquiry where a buyer should request the full section designation or mill table.

For example, a standard 300 × 300 H-section with one set of web/flange thicknesses can have a very different mass from a heavy-series 300 × 300 section. If the quoted mass does not match the standard dimensional line you are using, do not “repair” the designation by guessing thicker dimensions.

How to find the closest European candidate

If a designer asks for a European candidate to screen against a JIS/GB section, compare at least:

1. overall depth;
2. flange width;
3. web thickness;
4. flange thickness;
5. root radius and clear web depth;
6. cross-sectional area and mass per metre;
7. second moments of area about both axes;
8. elastic and plastic section moduli;
9. radii of gyration;
10. torsional properties where relevant;
11. connection geometry.

A candidate that matches mass may still have the wrong flange width or minor-axis stiffness. A candidate that matches depth may still have a much thinner web.

For the main European families, see HEA, HEB, HEM and IPE sections.

“Closest smaller” and “closest larger” need a defined criterion

Requests such as:

give me the closest smaller and closest bigger section

are ambiguous.

“Smaller” could mean:

• lower mass per metre;
• smaller depth;
• thinner flange;
• lower section modulus;
• lower moment of inertia.

“Bigger” has the same problem in reverse.

Before comparing sections, define the property that must be maintained. For a bending member this may be a section modulus or moment of inertia; for a column, buckling properties and radii of gyration may dominate; for a connection, flange and web geometry may be decisive.

Substitution is an engineering deviation, not a purchasing shortcut

As with UB, UC and American W-sections vs European HE/IPE profiles, cross-system substitution should not be treated as normal or recommended procurement practice.

It can occasionally be useful to identify a candidate alternative when a very small quantity must be collected from stock and the specified section is unavailable. But the buyer or stockholder should only propose the candidate.

The structural designer or responsible engineer must approve the substitution.

That approval should be based on the actual section properties and connection implications, not on a statement such as “HEB 300 is close to JIS H300×300.”

Grade equivalence is a separate question

Even after a dimensional candidate has been identified, the steel grade still has to be checked separately.

A Japanese or Chinese section may be supplied under a JIS or GB material standard, while the European project may specify an EN grade such as S355J2, S355M or an offshore grade.

Do not combine the section-shape comparison and grade-equivalence decision into one step.

For grade methodology, see How to compare steel grades across standards.

Use published mass rather than a rough geometric approximation

For standardized rolled sections, the published mass per metre should normally be used. Root radii and rolling geometry mean that a simple rectangle-based calculation can differ from the tabulated nominal mass.

See How to calculate or look up steel-section unit weight.

MetalMate takeaway

JIS, GB and EN H/I-section series should be compared property by property, not converted by name or nominal depth. Request the complete source-section geometry, identify only a candidate EN profile, and treat any actual substitution as a designer-approved engineering deviation.

Related Knowledge

• HEA, HEB, HEM and IPE sections
• How to read beam dimensions
• UB, UC and W-sections vs HE/IPE
• Steel-section unit weight

References

• Japanese Standards Association, JIS G 3192:2024 — Dimensions, shape, mass and permissible variations of hot rolled steel sections: https://webdesk.jsa.or.jp/books/W11M0090/index/?bunsyo_id=JIS+G+3192%3A2024
• China National Standard Information Public Service Platform, GB/T 11263-2024 — Hot rolled H and cut T section steel: https://openstd.samr.gov.cn/bzgk/std/newGbInfo?hcno=8894AAFBAE28DF71A29374720910304F
• NEN, EN 10365:2026 — Hot rolled steel channels, I and H sections — Dimensions and masses: https://www.nen.nl/en/nen-en-10365-2026-en-353950
• JFE Steel, Wide Flange Shapes catalogue — JIS G 3192 metric series: https://www.jfe-steel.co.jp/en/products/shapes/catalog/d1e-101.pdf