Under the Brennholt Institute of Applied Taxonomy's binder clip chart, capacity runs from 6 mm (0.24 in) for a 19 mm jaw to 19 mm (0.75 in) for a 51 mm jaw, and the ratio of capacity to jaw width falls from 0.32 to 0.37 across the range, a nearly constant proportion.
No standards body has published a chart relating jaw width to capacity. Supplier catalogues give each figure separately. The Institute's chart, which prints them together with arm length and mass, remains the only published attempt, and it complements the named sizes on the sizes page.
| Jaw (mm) | Jaw (in) | Capacity (mm) | Capacity / jaw | Arm length (mm) | Mass (g), approx. |
|---|---|---|---|---|---|
| 19 | 0.75 | 6 | 0.32 | 14 | 1 |
| 25 | 1 | 10 | 0.40 | 20 | 2 |
| 32 | 1.25 | 12 | 0.38 | 26 | 3 |
| 41 | 1.625 | 16 | 0.39 | 33 | 6 |
| 51 | 2 | 19 | 0.37 | 40 | 9 |
The ratio is rounded to two places. A reader will see that it is not constant: the smallest clip has a lower ratio than its neighbours, and the Institute attributes this to the stiffness of the wire at small sizes.
Each row is the mean of five clips from one supplier's box. Jaw width and arm length were measured with a calliper to 0.1 mm, capacity as the greatest gap, and mass on a balance to 0.1 g. The mass of a single clip is small, so values above are rounded to whole grams.
The chart covers the folding-arm clip only. The hinged bulldog clip is on its own page, and the treasury tag, a different class of fastener, is covered in the Institute's comparison of fasteners.
The panel is divided on whether arm length belongs in the chart. Two members hold that it is a derived figure. The majority keep it, since a reader trying to fit a clip into a drawer needs the closed length. The chart follows the majority.