Every AISC W-shape has an exact metric designation — W12x26 is W310x38.7, the identical rolled section with the depth in millimetres and mass in kg/m instead of inches and lb/ft. Beyond that soft-metric rename, most common W sizes also have a close British UB match (often within 1% on weight for the deeper sizes) and a looser European HE or IPE match. The chart below covers all three, built from published AISC, British, and ArcelorMittal catalog data.
One distinction before you use it: the metric W designation is the same piece of steel. A UB or HE "equivalent" is a different rolled section that happens to land close on depth and weight. The first is a unit conversion; the second is a substitution that needs an engineer's sign-off.
How to use the cross-reference chart
Three situations put this chart in front of an estimator:
- A metric drawing lands on your desk and you need to know what W310x38.7 or UB 406x178x60 weighs in units your pricing spreadsheet understands.
- You're quoting export work or a job designed to Eurocode/BS, and the shop needs to know whether domestic W-shape stock can cover the callouts.
- Mixed drawing sets — a European designer, an American fabricator, and a set of sheets where page S-201 says W530x92 and page S-305 says W21x62. (Those are the same beam.)
Read the chart left to right: imperial W designation, its exact soft-metric name, the closest UB, and the closest HE/IPE. Weights are catalog values, not conversions rounded twice.
What is the metric equivalent of a W12x26?
The exact metric equivalent of a W12x26 is W310x38.7 — same section, 310 mm deep, 38.7 kg/m (26 lb/ft × 1.488). On a metric drawing from a mill that rolls to ASTM A6M, that is the designation you'll see.
If the question is "what British or European section is closest to a W12x26," the answers are:
| Standard | Closest section | Weight | Depth | vs. W12x26 |
|---|---|---|---|---|
| Exact (soft metric) | W310x38.7 | 38.7 kg/m | 310 mm | identical |
| British (UB) | UB 305x127x37 | 37.0 kg/m | 304 mm | 4% lighter, narrower flange |
| British (UB) | UB 305x165x40 | 40.3 kg/m | 303 mm | 4% heavier, similar flange |
| European (IPE) | IPE 300 | 42.2 kg/m | 300 mm | 9% heavier |
None of the substitutes is a drop-in. UB 305x127x37 gives up flange width (127 mm vs. the W12x26's 165 mm), which matters for lateral-torsional buckling and connection geometry. IPE 300 carries 9% more steel you're paying for. For pricing a budget number, any of them gets you close; for fabrication, the engineer picks.
W-shape to UB conversion chart (common sizes)
British Universal Beams and American W-shapes descend from similar rolling practice, and at the deeper sizes they converge almost completely — several UB sizes are dimensionally the same section as the metric W. Weights below are catalog kg/m; the lb/ft column is the AISC designation weight.
| AISC W-shape | lb/ft | Metric W (exact) | Closest UB | UB kg/m | UB depth |
|---|---|---|---|---|---|
| W8x18 | 18 | W200x26.6 | UB 203x133x25 | 25.1 | 203 mm |
| W10x22 | 22 | W250x32.7 | UB 254x146x31 | 31.1 | 251 mm |
| W12x26 | 26 | W310x38.7 | UB 305x127x37 | 37.0 | 304 mm |
| W14x30 | 30 | W360x44.6 | UB 356x171x45 | 45.0 | 351 mm |
| W16x40 | 40 | W410x60 | UB 406x178x60 | 60.1 | 406 mm |
| W18x50 | 50 | W460x74 | UB 457x191x74 | 74.3 | 457 mm |
| W21x62 | 62 | W530x92 | UB 533x210x92 | 92.1 | 533 mm |
| W24x84 | 84 | W610x125 | UB 610x229x125 | 125.0 | 612 mm |
| W27x94 | 94 | W690x140 | UB 686x254x140 | 140.0 | 684 mm |
| W30x116 | 116 | W760x173 | UB 762x267x173 | 173.0 | 762 mm |
| W33x141 | 141 | W840x210 | UB 838x292x210 | 210.0 | 846 mm |
| W36x160 | 160 | W920x238 | UB 914x305x238 | 238.0 | 915 mm |
Notice the pattern break at W16x40. From there down the table, the UB match is essentially exact — UB 457x191x74 and W18x50 are the same 74 kg/m of steel at the same 457 mm depth. Below W16, the two series drift apart: the light UBs come in narrower flange families (127, 133, 146 mm) that don't line up with American proportions, so every match is a compromise on flange width or weight.
For the full run of American sizes and their properties, see the wide-flange beam size guide.
W-shape to HE/IPE conversion chart
European drawings call out two I-section families: IPE (narrow-flange beams, the workhorses) and HE (wide-flange columns and heavy beams, in A/B/M weight classes — HEA vs HEB vs HEM explained here). The matches are looser than UB because the European series uses different depth increments and flange proportions.
| AISC W-shape | kg/m (exact) | Closest HE/IPE | kg/m | Depth | Notes |
|---|---|---|---|---|---|
| W8x18 | 26.8 | IPE O 200 | 25.1 | 202 mm | beam-proportioned |
| W8x31 | 46.1 | HE 220 A | 50.5 | 210 mm | column-proportioned |
| W10x22 | 32.7 | IPE O 240 | 34.3 | 242 mm | beam |
| W10x49 | 72.9 | HE 260 A | 68.2 | 250 mm | column |
| W12x26 | 38.7 | IPE 300 | 42.2 | 300 mm | beam |
| W12x65 | 96.7 | HE 320 A | 97.6 | 310 mm | column |
| W16x40 | 59.5 | IPE A 400 | 57.4 | 397 mm | beam |
| W18x50 | 74.4 | IPE 450 | 77.6 | 450 mm | beam |
| W21x62 | 92.3 | IPE A 550 | 92.1 | 547 mm | deeper, lighter web |
| W24x84 | 125.0 | IPE 600 | 122.0 | 600 mm | beam |
| W30x116 | 172.6 | IPE 750x173 | 173.0 | 762 mm | near-exact |
| W36x160 | 238.1 | HE 900 A | 252.0 | 890 mm | no close IPE this deep |
The split in the notes column is the useful part. American practice uses W-shapes for everything; European practice splits the job. If the W-shape is beam-proportioned (W12x26, W16x40 — deep and narrow), the match lives in the IPE series. If it's column-proportioned (W8x31, W10x49, W12x65 — square-ish, wide flanges), the match is an HE A-series. Send a W10x49 hunting through IPE tables and you'll find nothing sensible.
More on the full European family — UPN channels, equal angles, the works — in the European steel sections guide.
Why "equivalent" is approximate: depth, weight, and capacity trade-offs
Three things keep a cross-standard match from being a true substitution:
Depth increments don't align. AISC steps 8-10-12-14-16 inches (203-254-305-356-406 mm); IPE steps 200-220-240-270-300. A W10 (254 mm) falls between IPE 240 and IPE 270 — whichever you pick changes connection elevations and deck bearing.
Flange geometry drives capacity, not just weight. UB 305x127x37 weighs within 4% of a W12x26 but carries a flange 38 mm narrower. Section modulus, lateral bracing requirements, and bolt gauge all shift. Two sections with identical kg/m can differ meaningfully in bending capacity.
Material grades differ. A992 (Fy = 50 ksi / 345 MPa) is the American default; S355 (355 MPa) is the closest common European grade, but S275 shows up constantly on older and lighter European work. A dimensionally perfect swap at the wrong grade is still the wrong beam.
Use the chart for estimating, availability checks, and reading foreign drawings. Any actual substitution on a real job goes through the EOR.
How do you convert W-shape weights from lb/ft to kg/m?
Multiply lb/ft by 1.488 to get kg/m. Going the other way, multiply kg/m by 0.672 to get lb/ft.
Worked examples:
- W12x26: 26 lb/ft × 1.488 = 38.7 kg/m — matching its W310x38.7 metric designation exactly
- W21x62: 62 × 1.488 = 92.3 kg/m → metric W530x92
- UB 406x178x60: 60.1 kg/m × 0.672 = 40.4 lb/ft — which is why its American twin is the W16x40
The designation numbers do the arithmetic for you on both sides: the last number in a W-shape callout is lb/ft, and the last number in a metric W or UB callout is kg/m. If a takeoff line's weight disagrees with its designation by more than a rounding error, something upstream is wrong — usually a mis-read label.
Takeoff tip: mixed-standard drawing sets
Mixed-standard sets are where these charts stop being trivia. A German-designed warehouse built in Texas, a UK consultant on a Gulf project spec'ing UBs with American deck — one drawing set, two or three designation systems, and a takeoff that has to land in one unit system at the end.
The failure mode is quiet: W530x92 on the framing plan and W21x62 in the general notes are the same beam, but a manual takeoff that doesn't recognize that counts them as two line items — or worse, double-counts the tonnage. The reverse failure is treating UB 533x210x92 as if it were also that same beam; it's a near-twin, not the same section, and the mill order needs to say which one.
This is a problem worth automating. SteelFlo's detection reads AISC, British/Indian, European, Australian, Chinese, and cold-formed designations off the same drawing set — 4,500+ sections across 6 standards — assigns each label to its actual standard, and carries the correct catalog weight for each, hitting 95-99% accuracy with AI detection plus human verification of every flagged item. What it never does is silently merge a UB with its W-shape near-equivalent: the count you review is the count on the drawings. More on running non-AISC and mixed sets in steel takeoffs beyond AISC, and the full searchable section database is at /shapes.
Need a fast answer on one beam rather than a whole drawing set? The free steel weight calculator covers every section in this article — pick a W, UB, HE, or IPE, enter a length, and get weight in either unit system. No signup, and if you want to run a full drawing, your first 3 takeoffs are free.