What Is B5 Paper? Size, Comparison, and How to Use It Well

B5 is an ISO paper size measuring 176 by 250 mm (6.9 by 9.8 in). It sits between A5 and A4: about 30% smaller in area than A4, with around 42% more writing room than A5. That makes B5 a middle-ground size with space to plan a full day, in a footprint that still carries easily.

How does B5 compare to A4 and A5?

All three are standard ISO sizes. The table shows the exact dimensions and what each size is suited to.

Size	Millimeters	Inches	Well suited to
A5	148 × 210 mm	5.8 × 8.3 in	Minimal, pocketable carry
B5	176 × 250 mm	6.9 × 9.8 in	More writing room without desk-bound bulk
A4	210 × 297 mm	8.3 × 11.7 in	Full-page, desk-based work

Put simply, B5 is roomier than A5 and lighter to carry than A4. A5 is excellent when the goal is the smallest possible footprint that still fits a bag or a coat pocket. B5 gives you noticeably more room to write, roughly 42% more area than A5, while staying well short of A4's full-desk size.

Why choose B5 for everyday carry?

A4 is the natural size for the desk, but it is large to carry and can feel oversized for a day of meetings and lists. B5 keeps most of that writing room, about 30% less area than A4, in a size that sits comfortably in one hand and slides into most bags.

That is the reason B5 anchors the Griffin Opus system. There is space to lay out a full day, capture a real set of meeting notes, or sketch a project, without carrying a full sheet of A4 everywhere you go. It is the size that keeps up with a working day rather than tying you to a desk.

How do you make the most of a B5 page?

B5 gives you enough room to be deliberate. The trick is to treat that room as structure, not just extra space to fill.

One clear job per page. A single page holds a whole day, one meeting, or one project. Keeping one job per page is what makes B5 feel calm instead of crowded.
Use a column and a margin. A main column for the work and a narrow margin for dates, times, or checkboxes keeps everything legible and easy to scan later.
Leave breathing room. There is enough width that you do not need to cram. White space around your notes makes the important lines stand out.
Pair the right insert. Match the page to the task: a Daily Focus page for the day, a Smart Meeting page for a call, a Dot Grid page for open thinking.

Griffin Opus B5 inserts come 50 sheets each, printed on 80gsm smooth uncoated paper in a soft ivory that is easy on the eye and holds ink cleanly. You can build a system from the pages that match how you actually work.

Quick answers

What is B5 paper size?

B5 is an ISO paper size measuring 176 by 250 mm, or 6.9 by 9.8 inches. It sits between the smaller A5 and the larger A4.

Is B5 bigger than A5?

Yes. B5 (176 × 250 mm) is larger than A5 (148 × 210 mm), with roughly 42% more writing area. A5 remains an excellent choice when the smallest, most pocketable footprint is the priority.

How much smaller is B5 than A4?

B5 is about 30% smaller in area than A4. A4 measures 210 by 297 mm, while B5 measures 176 by 250 mm, so B5 keeps most of the writing room in an easier-to-carry size.

Is B5 a good notebook size for carrying?

Yes. B5 offers more writing room than A5 while staying noticeably lighter and smaller than A4, which makes it a strong middle-ground size for people who write on the move.

Will the right notebook size help make daily planning easier?

It can. A page that is too small forces you to cram, and a cramped page is harder to read back and act on. B5 gives room to lay out a whole day without squeezing, so your plan stays legible and easy to scan. For many people, the right size helps make planning less fiddly.

Does a less cramped page help make a plan easier to read and act on?

For many people, yes. When a whole day is crammed onto a small page, everything competes for attention. B5's extra writing room lets you leave space between items, so the important lines stand out and the page reads cleanly. It is a practical difference in how the page looks, and it helps make a plan easier to take in at a glance.