Short answer
The UK uses Universal Beams (UB) and Universal Columns (UC) in place of AISC W shapes. A UB is named depth x width x mass in millimetres and kg/m, like 305x165x40 UB. UB and UC sections are close to W shapes in purpose, but no UK section is an exact match, so a "UK equivalent" is a nearby substitute rather than the same piece of steel.
How UB and UC designations read
A UB or UC name has three numbers and a suffix: depth (mm) x flange width (mm) x mass (kg/m). So 203x133x25 UB is a beam about 203 mm deep and 133 mm wide, weighing 25 kg/m (25.1 in the table). A UC works the same way: 254x254x73 UC is 73.1 kg/m.
The split between UB and UC is a proportion rule: UBs are deeper than they are wide and are mostly used as beams, while UCs are squarer and used as columns. AISC W shapes cover both jobs under one letter, so one W family may map to both UB and UC.
Closest matches for a W12x26
A W12x26 is 12.22 in deep, 6.49 in wide and 26 lb/ft (38.7 kg/m). Nearby UK sections:
| Section | Mass | Depth | Comment |
|---|---|---|---|
| 305x127x37 UB | 37.0 kg/m | about 304 mm | Slightly lighter, narrower flange |
| 305x165x40 UB | 40.3 kg/m | 303.4 mm | Slightly heavier, similar flange |
Neither is a drop-in. Substituting one for the other is a design decision for the engineer, not an estimating shortcut. For a budget price either gets you close, and for a bid you price what the drawings call out. See the full cross-reference in W-shape metric equivalents.
What other UK sections should you know?
- PFC: parallel flange channel, the UK counterpart of an American channel. 100x50x10 PFC is 10.2 kg/m.
- SHS, RHS, CHS: square, rectangular and circular hollow sections, usually EN 10210 hot-finished or EN 10219 cold-formed.
- Angles: written leg x leg x thickness, such as L 100x50x6.
- Celsius and Hybox: hot-finished hollow sections from specific producers, found on some drawings.
UK structural steel is usually grade S355 on new work, with S275 on older drawings. A992 (50 ksi, about 345 MPa) is the US default, so the grades are comparable but not the same. Check the general notes.
How do you handle UK drawings in an estimate?
Take off in metric. Lengths are in mm or m, mass in kg/m, and totals in tonnes. Convert to imperial only if your pricing is in lb, using 0.67197 lb/ft per kg/m (see How do you convert kg/m to lb/ft?).
SteelFlo reads UK sections directly and keeps jobs in metric, so a UB 305x165x40 is read as that section with its 40.3 kg/m mass, not coerced into an American size. Every UB, UC and PFC has a page in the shape database, including 203x133x25 UB and 254x254x73 UC.
A few UB and UC sizes in both units
| Section | kg/m | lb/ft | Depth (mm) |
|---|---|---|---|
| 203x133x25 UB | 25.1 | 16.87 | 203.2 |
| 305x127x37 UB | 37.0 | 24.86 | 304.4 |
| 305x165x40 UB | 40.3 | 27.08 | 303.4 |
| 457x191x67 UB | 67.1 | 45.09 | 453.4 |
| 152x152x23 UC | 23.0 | 15.46 | 152.4 |
| 254x254x73 UC | 73.1 | 49.12 | 254.1 |
Multiply kg/m by 0.67197 for lb/ft. The mass in the name is rounded, so the table value is slightly different (25 in the name, 25.1 in the table for the 203x133 beam). Use the table value for weights.
Does a UK drawing set read differently from a US one?
Often, yes. UK drawings use millimetres, member marks tied to schedules, and notes referring to BS EN standards. Typical wording includes "steel grade S355JR", "to BS EN 10025", and "UB" or "UC" next to a size. Connections are usually designed by the fabricator to a specified reaction, which is covered by the delegated design note. See Delegated connection design and estimating.
Even the arrangement of sheets differs. If you are used to American S-series sheets, take a moment to learn the local sheet numbering before you start counting.
Is a UB the same as a W shape in the shop?
No. They are rolled to different standards from different mills with different dimensions, tolerances and grades. They do the same job, and engineers do swap them in design, but a fabricator cannot treat them as interchangeable without approval. For estimating, price what the drawing calls out. If a US shop is bidding a UK-designed job, ask the engineer and the buyer whether the specified sections are available locally or must be imported, because that changes price and lead time.
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