ISO 838 (2-Hole) vs. US 3-Hole
Comparing 2 standards across 9 specifications. 9 key differences identified.
ISO 838 (DIN 821) is the international standard for 2-hole paper punching, specifying two circular holes spaced exactly 80.0 mm ± 0.5 mm apart with a diameter of 6.0 mm ± 0.5 mm, positioned 12.0 mm ± 1.0 mm from the binding edge of the sheet. It is the universal standard for ring binders and lever arch files across Europe, Asia, Africa, and Latin America.
The North American 3-Hole Standard is the ubiquitous paper punching system in the United States, Canada, and Mexico for 8.5 × 11-inch US Letter paper. Specifying three circular holes spaced exactly 4.25 inches (107.95 mm) apart (an 8.5-inch total span) with 5/16-inch (7.94 mm) hole diameters, it is the standard for 3-ring school and business binders.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Center-to-Center Hole Spacing
|
80.0 ± 0.5 mm (3.15 in) | 4.25 in (107.95 mm) |
|
Hole Diameter
|
6.0 ± 0.5 mm (0.24 in) | 5/16 in (7.94 mm) standard or 9/32 in (7.14 mm) |
|
Edge Distance to Hole Center
|
12.0 ± 1.0 mm (0.47 in) | 0.375 to 0.50 in (9.5 to 12.7 mm) |
|
Centering Standard
|
Holes are centered symmetrically along the paper's long edge (A4) or short edge (A5) | — |
|
Target Paper Pairing
|
ISO 216 A4 (210 × 297 mm) and A5 (148 × 210 mm) | — |
|
Binder Compatibility
|
2-ring binders, European lever arch files (Leitz Ordner, Esselte, Rexel) | — |
|
Total Outer Hole Span
|
— | 8.50 in (215.90 mm — from top hole center to bottom hole center) |
|
Top & Bottom Margins on US Letter
|
— | Exactly 1.25 in (31.75 mm) from sheet edge to outer hole centers |
|
Primary Applications
|
— | School 3-ring binders (Avery, Wilson Jones), corporate training manuals, loose-leaf filler paper |