Why Notebook Size Standards Exist
Notebook sizes may appear arbitrary at first glance, but most commonly used formats follow established standards or long-standing conventions. These sizes exist to support printing efficiency, consistency, and predictable scaling across paper products.
Understanding how common notebook sizes relate to one another helps clarify why certain formats appear repeatedly across journals, planners, and notebooks worldwide.
The Role of ISO Paper Sizes
The A-series sizes (A5 and A6) are derived from the ISO 216 paper standard, which defines paper dimensions using a consistent mathematical ratio. Each size is exactly half the area of the previous one while maintaining identical proportions.
This system allows documents, books, and notebooks to scale cleanly without redesigning layouts.
Non-ISO Formats and Legacy Sizes
In addition to ISO sizes, several notebook formats emerged through travel, publishing, and personal organization practices rather than formal standards.
Formats such as Pocket, Traveler’s Notebook (TN), and Passport sizes developed to meet portability and binding preferences, particularly in travel and journaling contexts.
Common Notebook Sizes at a Glance
The chart below outlines the most widely used notebook sizes and their approximate dimensions.
| Size Name | Approx. Dimensions | Standard Type |
|---|---|---|
| A5 | 148 × 210 mm (5.8 × 8.3 in) | ISO 216 |
| A6 | 105 × 148 mm (4.1 × 5.8 in) | ISO 216 |
| ≈ 90 × 140 mm (3.5 × 5.5 in) | Non-standard | |
| Traveler’s Notebook (Regular) | ≈ 110 × 210 mm (4.3 × 8.3 in) | Legacy format |
| Passport | ≈ 90 × 125 mm (3.5 × 4.9 in) | Legacy format |
How These Sizes Relate to One Another
ISO sizes scale predictably, while non-ISO formats often overlap partially with A-series dimensions. For example, A6 and Pocket formats are close in size but differ enough to prevent interchangeability.
Traveler’s Notebook and Passport formats prioritize aspect ratio and binding style over mathematical scaling, which explains their unique proportions.
Why Naming Conventions Can Be Confusing
Notebook size names are often reused across brands with slight dimensional variations. A “Pocket” notebook from one maker may differ subtly from another, even when the label is the same.
ISO sizes remain the most consistent because their dimensions are standardized internationally.
Why Size Reference Matters
Understanding notebook sizes as a reference—not a recommendation—helps clarify compatibility, layout expectations, and long-term usability.
This reference framework underpins systems designed around standardized formats, including structured offerings within our leather journal collection.
A Reference, Not a Verdict
Notebook sizes are tools shaped by standards, tradition, and use cases. This guide exists to explain the landscape, not to prescribe a choice.
Once sizes are understood clearly, they fade into the background—allowing the focus to remain on writing itself.