A5 vs B6
B6 (125 × 176 mm) sits just below A5 (148 × 210). It is the ISO B size between A6 and A5, a common pocket-book and diary trim, about 20 mm smaller each way than A5.
Compare a Different Pair
A5 and B6, Side by Side
| A5 | B6 | Difference | |
|---|---|---|---|
| Millimetres | 148 × 210 | 125 × 176 | 23 × 34 mm |
| Inches | 5.83 × 8.27 | 4.92 × 6.93 | 0.91 × 1.34 in |
| Centimetres | 14.8 × 21.0 | 12.5 × 17.6 | |
| Area | 0.0311 m², 31,080 mm² | 0.022 m², 22,000 mm² | 1.41× |
| Aspect ratio | 1 : 1.419 (√2) | 1 : 1.408 (√2) | same |
What Is Lost Printing One on the Other
At 100% scale, both centred, nothing resized. A positive figure on the wider or taller side is cropped; on the other it is a blank margin.
| Axis | Gap | A5 onto B6 | B6 onto A5 |
|---|---|---|---|
| Width | 11.5 mm (0.45 in) each side | A5 loses it | blank band |
| Height | 17 mm (0.67 in) each end | A5 loses it | blank band |
Scale-to-Fit Percentages
The figure to type into a printer or PDF dialog to scale one to fit inside the other:
| B6 to fit A5 | 118% | leaves a thin border on one pair of edges |
|---|---|---|
| A5 to fit B6 | 84% | leaves a thin border on one pair of edges |
The two share the 1 : √2 shape but are not one halving apart, so a fit-to-page scale still leaves a small border.
Which Should You Use?
A5 for a notebook or planner you write in at a desk. B6 when you want the same format to fit a jacket pocket or a small bag, accepting a narrower page.
Beyond the Measurements
Envelopes: A5 fits C5, C6; B6 has none.
Worth Knowing
B6 only really makes sense once you have held a Japanese paperback or a pocket planner. It is deliberately between A6 and A5: bigger than a pocket diary, smaller and lighter than a full A5. Choosing a notebook, the honest test is where it will live. On a desk, A5. In a coat pocket or a handbag, B6, and you give up about a fifth of the writing area for it. The two do not nest, so do not expect A5 inserts to fit a B6 cover.
Frequently Asked Questions
Is A5 bigger than B6?
A5 is bigger. It is 148 × 210 mm against 125 × 176 mm for B6, about 1.41 times the area.
What is the difference between A5 and B6?
B6 (125 × 176 mm) sits just below A5 (148 × 210). It is the ISO B size between A6 and A5, a common pocket-book and diary trim, about 20 mm smaller each way than A5.
Can you print B6 on A5?
Not at full size without a change. Shrink B6 to 118% to fit A5, which leaves a thin border, or print at 100% and lose 11.5 mm off each side and 17 mm top and bottom.
✓ Dimensions per the standards on the A5 and B6 pages. Differences and scale factors computed. Reviewed . Editorial Process →