A3 vs JIS B3

Q: Which is bigger, A3 or JIS B3?

JIS B3 — 364 × 515 mm against 297 × 420 mm, which is 50.3% more area.

	A3	JIS B3
Millimetres	297 × 420	364 × 515
Inches	11.69 × 16.54	14.33 × 20.28
Centimetres	29.7 × 42	36.4 × 51.5
Aspect ratio	1:1.41	1:1.41
Area	1247.4 cm²	1874.6 cm²

Which is bigger

A3 and JIS B3 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 B3, by 50.3% in area. JIS B3 is 67 mm wider than A3. JIS B3 is 95 mm taller.

Printing one on the other

A A3 page fits inside JIS B3 whole — print it at 100% and you get a 33.5 mm border down each side and 47.5 mm top and bottom.

You want	Set the print scale to	Leaves
A3 artwork on JIS B3 paper	122.6%	0 × 0.3 mm margin
JIS B3 artwork on A3 paper	81.6%	0.1 × 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

Both sheets have the same 1:1.41 proportions, so artwork scales between them without any cropping or extra margin — only the size changes.

Frequently asked questions

What is the difference between A3 and JIS B3?

A3 is 297 × 420 mm and JIS B3 is 364 × 515 mm. JIS B3 is the larger of the two by 50.3% in area.

Can I print A3 on JIS B3?

Yes, at 100% — A3 is smaller on both edges, so it lands inside JIS B3 with a border all round.

Which is bigger, A3 or JIS B3?

JIS B3 — 364 × 515 mm against 297 × 420 mm, which is 50.3% more area.

Related comparisons

A3 in full · JIS B3 in full · All size comparisons · All paper sizes