Quick Answer
A5 (about 5.8 x 8.3 inches, or 148 x 210 mm) is often described as the most popular journal size because it balances writing room with portability. Smaller sizes such as A6 are easier to carry, while larger sizes such as B5 and A4 give more room for planning, sketching, and note-taking. The best size is the one you will actually open regularly.
Journal Notebook Size Chart
Sizes below are approximate, and brands often make slightly different versions, so check the listing for exact measurements.
| Size | Millimeters | Inches | Typical feel |
|---|---|---|---|
| A6 | 105 x 148 | 4.1 x 5.8 | Pocket or small bag |
| A5 | 148 x 210 | 5.8 x 8.3 | Everyday journal |
| B5 | 176 x 250 | 6.9 x 9.8 | Roomy desk notebook |
| A4 | 210 x 297 | 8.3 x 11.7 | Large, document-sized |
Some brands also sell pocket, passport, and “A5+” or similar variants that are slightly wider or taller than the standard. Treat these labels as brand-specific.
A-Series and B-Series Sizes
Most of the world outside North America uses the ISO paper system. In the A series, each size is half the one before it: A4 folded in half becomes A5, and A5 folded in half becomes A6. B sizes sit between A sizes, which is why B5 is a little bigger than A5. North American sizes such as Letter are separate; our article on whether notebook paper is letter size explains how they compare.
Common Sizes in Detail
A6
Small enough for a coat pocket or a small bag. It suits short daily entries, gratitude lists, quotes, and travel notes. The limited page area is a drawback for long writing or elaborate layouts.
A5
Large enough to write comfortably and still light enough to carry in a bag. It is the size many bullet journal notebooks use, and it is a sensible default if you are unsure.
B5
A bit larger than A5. It gives more space for planning spreads, mind maps, and sketches, and it sits better on a desk than in a small bag.
A4
Document-sized pages offer plenty of room for notes and large drawings, but the book is heavier and less portable. It is often a better fit for study or office use than for casual journaling.
Pocket and passport sizes
These are smaller than A6 in some brands and are often used in traveler-style notebook covers. They suit short notes and lists.
Which Size for Which Kind of Journaling?
- Daily reflection or gratitude: A6 or A5.
- Bullet journal: A5 is common (see bullet journal sizes), while B5 is useful if you want larger weekly spreads. Dotted or grid paper is typical.
- Travel journal: A6 or a pocket size for portability, or A5 if you like to collage.
- Art or sketch journal: B5 or A4 for room to work (see visual journal examples).
- Work or study notes: A5 to A4, depending on how much you carry.
How to Decide
- Where will it live? Bag or pocket points to smaller sizes. A desk points to larger ones.
- How much do you write? Long entries feel cramped in small books.
- Do you decorate? Larger pages give more design room.
- Does it match your other supplies? Check that pen cases, covers, or inserts will fit, and consult our journal supplies list.
- Binding and weight matter too. A thick hardbound A4 can be heavy. See types of notebook binding for how binding affects use.
If you cannot decide, A5 is a low-risk starting point.
FAQ
Which journal size is best?
There is no single best size. A5 is a popular all-rounder, A6 is better for portability, and B5 or A4 are better for planning and drawing.
What size is A5?
About 148 x 210 millimeters, or roughly 5.8 x 8.3 inches.
What is the size of A6 paper in inches?
About 4.1 x 5.8 inches (105 x 148 mm).
Which notebook is best for bullet journals?
Many people use an A5 dotted notebook, but the right choice depends on your layout and how much you carry. Our organization notebook ideas article covers setup ideas for any size.