Under the Brennholt Institute of Applied Taxonomy's distinction, a bulldog clip is a sprung clip with hinged jaws, while a binder clip is a clip with a spring-steel body and folding wire arms, and the two are not the same object although catalogues often use the names interchangeably. Bulldog clips are recorded by jaw width, from 38 mm (1.5 in) to 75 mm (3 in).
No standards body has distinguished the two objects, and usage differs between English-speaking regions. The Institute's distinction by mechanism, not by name, remains the only published attempt to separate them.
| Feature | Binder clip | Bulldog clip |
|---|---|---|
| Body | Folded spring steel, triangular | Two hinged jaws |
| Spring | Body itself | Separate coil or leaf spring |
| Handles | Removable wire arms | None, jaws pressed by hand |
| Typical jaw width | 19 to 51 mm | 38 to 75 mm |
The binder clip is covered on its own sizes page.
| Jaw (mm) | Jaw (in) | Typical capacity (mm) |
|---|---|---|
| 38 | 1.5 | 12 |
| 50 | 2 | 18 |
| 63 | 2.5 | 25 |
| 75 | 3 | 30 |
Capacities are approximate and are given to the nearest millimetre; the spring tension varies more between bulldog clips than between binder clips.
A name such as bulldog or crocodile is applied to hinged clips of very different make in different markets. The Institute does not rely on the name. It records the mechanism, the jaw width and the capacity, and treats any further label as a trade term. This is the same method applied to office fasteners on the comparison page.
The panel is divided on whether the two belong in one class. Two members would merge them as spring clips. The majority keep them apart, since a stack that fits one will often not fit the other, and the Institute's tables follow the majority.