ISO 838 (4-Hole) vs. US 2-Hole Top Punch
Comparing 2 standards across 9 specifications. 9 key differences identified.
The ISO 838 4-Hole extension (commonly known in Europe as the '888' format) specifies four holes spaced at three consecutive 80.0 mm intervals (80–80–80 mm, spanning 240.0 mm total) with standard 6.0 mm hole diameters. It is standard for heavy A4 4-ring presentation binders and archival document protectors to prevent page sagging.
The US 2-Hole Top Punch (standardized at 2.75 inches / 69.85 mm center-to-center spacing) is the North American standard for punching the short top edge of US Letter or US Legal documents. Paired with 2-prong metal fasteners, heavy classification pressboard folders, and clipboard arches, it is standard for medical charts and legal court exhibits.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Hole Diameter
|
6.0 ± 0.5 mm | 5/16 in (7.94 mm) standard or 9/32 in (7.14 mm) |
|
Edge Distance to Hole Center
|
12.0 ± 1.0 mm | 0.375 in (9.53 mm) from top edge |
|
Primary Applications
|
4-ring A4 presentation binders, clear plastic sheet protectors, heavy catalog binders | Hospital patient medical charts, courtroom deposition binders, real estate mortgage closings |
|
Hole Interval Geometry
|
Three 80 mm gaps: 80 mm – 80 mm – 80 mm (total outer span: 240.0 mm) | — |
|
Outer Hole Margin on A4
|
28.5 mm from top and bottom edges of an A4 sheet (297 mm length) | — |
|
Backwards Compatibility
|
Middle two holes match standard ISO 838 2-hole binders exactly | — |
|
Center-to-Center Hole Spacing
|
— | 2.75 in (69.85 mm) |
|
Placement Orientation
|
— | Centered along the top 8.5-inch edge of US Letter or US Legal sheets |
|
Fastener Pairing
|
— | 2-prong metal compressor fastener prongs (2.75 in base) |