A4 vs JIS B4

Q: Which is bigger, A4 or JIS B4?

JIS B4 — 257 × 364 mm against 210 × 297 mm, which is 50% more area.

	A4	JIS B4
Millimetres	210 × 297	257 × 364
Inches	8.27 × 11.69	10.12 × 14.33
Centimetres	21 × 29.7	25.7 × 36.4
Aspect ratio	1:1.41	1:1.42
Area	623.7 cm²	935.5 cm²

Which is bigger

A4 and JIS B4 carry the same number and are not the same sheet. The Japanese B series is defined by area — JIS B0 is 1.5 square metres where A0 is 1 — so a JIS B sheet is half again the area of the A sheet of the same number, and about 22% longer on each edge. The number tells you where a sheet sits in its own series and nothing about which standard it belongs to.

JIS B4, by 50% in area. JIS B4 is 47 mm wider than A4. JIS B4 is 67 mm taller.

Printing one on the other

A A4 page fits inside JIS B4 whole — print it at 100% and you get a 23.5 mm border down each side and 33.5 mm top and bottom.

You want	Set the print scale to	Leaves
A4 artwork on JIS B4 paper	122.4%	0 × 0.5 mm margin
JIS B4 artwork on A4 paper	81.6%	0.3 × 0 mm margin

These are the numbers for the "custom scale" box in a print dialog. "Fit to page" computes the same thing, but knowing the figure tells you in advance whether the result will look deliberate or accidental.

Why the shapes matter

The proportions differ: A4 is 1:1.41 and JIS B4 is 1:1.42. That difference is why a layout moved between them never quite lines up — scale it to fit one edge and the other is left with 0.5 mm of unwanted margin.

Frequently asked questions

What is the difference between A4 and JIS B4?

A4 is 210 × 297 mm and JIS B4 is 257 × 364 mm. JIS B4 is the larger of the two by 50% in area.

Can I print A4 on JIS B4?

Yes, at 100% — A4 is smaller on both edges, so it lands inside JIS B4 with a border all round.

Which is bigger, A4 or JIS B4?

JIS B4 — 257 × 364 mm against 210 × 297 mm, which is 50% more area.

Related comparisons

A4 in full · JIS B4 in full · All size comparisons · All paper sizes