Choosing between a refillable A5 or A6 leather journal often comes down to more than size alone. Once you start using inserts regularly, factors like notebook fit, paper thickness, and how refills stack inside the cover can dramatically affect how satisfying the journal is to use.
If you’ve ever struggled with inserts feeling too tight, too loose, or awkward to write in, the issue is rarely the leather itself. It’s almost always about compatibility. This guide breaks down how refillable A5 and A6 leather journals differ when it comes to insert fit, thickness, and everyday usability.
Why Insert Fit Matters in Refillable Leather Journals
A refillable leather journal is a system, not just a notebook. The leather cover, the insert size, and the thickness of the paper all need to work together. When they don’t, you may notice pages bowing, covers refusing to close properly, or inserts shifting while you write.
Because leather has less flexibility than cardboard covers, refillable journals are less forgiving of poor fit. Choosing the right size and insert type from the start prevents frustration and helps the journal age properly over time.
Insert Fit in Refillable A5 Leather Journals
A5 refillable leather journals offer the most flexibility when it comes to inserts. The larger format allows for a wider range of notebook thicknesses and paper types without compromising usability.
Standard A5 inserts typically fit comfortably inside a well-made leather cover, even when using thicker paper or multi-signature notebooks. Writers who prefer heavier stock, longer entries, or structured layouts often find A5 more forgiving because the spine can accommodate more pages without strain.
This makes A5 an excellent choice if you:
- Write long-form entries or daily pages
- Use thicker paper to prevent ink bleed-through
- Prefer fewer insert changes throughout the year
The extra space also makes it easier to layer multiple inserts—such as one for planning and another for journaling—without the cover feeling overfilled.
Insert Fit in Refillable A6 Leather Journals
A6 refillable leather journals prioritise portability, which means insert fit becomes more critical. Because the format is smaller, thickness tolerance is reduced. Inserts that are too bulky can make the journal difficult to close or uncomfortable to write in.
Most A6 leather covers work best with slimmer inserts or single notebooks rather than stacked refills. Thin paper, fewer pages, and streamlined layouts help maintain a clean profile and comfortable writing angle.
A6 works particularly well if you:
- Prefer lighter, more compact inserts
- Change notebooks frequently
- Use your journal primarily on the move
When chosen thoughtfully, an A6 refillable journal feels nimble and intentional rather than cramped.
Thickness Considerations: How Much Is Too Much?
Thickness is one of the most overlooked aspects of refillable journal systems. A leather cover that looks perfect with a slim insert may struggle once a thicker notebook is added.
As a general guideline:
- A5 leather journals tolerate moderate-to-thick inserts more comfortably
- A6 leather journals perform best with slim, lightweight refills
Overfilling either size can stress the spine, distort the leather, and reduce writing comfort. Choosing inserts that suit the intended size preserves both function and longevity.
Notebook Compatibility Across Brands
One advantage of choosing standard A5 or A6 formats is broad compatibility with commonly available notebooks. However, not all inserts are created equal. Variations in spine width, cover stiffness, and paper count can affect how well a notebook fits inside a leather cover.
When selecting inserts, look for:
- True A5 or A6 dimensions (not proprietary sizing)
- Flexible covers rather than rigid cardboard
- Moderate page counts suited to the leather’s capacity
This is especially important for A6 systems, where even small deviations in thickness can impact usability.
Choosing Between Refillable A5 and A6 Leather Journals
If your priority is writing comfort, flexibility, and fewer insert swaps, A5 is often the better long-term choice. It adapts well to different paper types and supports more varied workflows.
If portability matters more than capacity, A6 offers a compact solution that integrates easily into everyday carry. With the right insert choice, it remains comfortable and reliable despite its smaller size.
Many journal users eventually use both—a larger A5 journal for focused writing at home or work, and a slimmer A6 journal for daily carry or travel.
Making a Refillable Journal Work for You
The best refillable leather journal is one where the cover and insert work in harmony. Paying attention to fit, thickness, and compatibility ensures the journal supports your habits rather than fighting them.
If you’d like to explore different formats and see how sizes compare side by side, browsing the full collection of leather journals can help you visualise which system fits your routine best.