Toolman

A3 vs JIS B4

A3JIS B4
Millimetres297 × 420257 × 364
Inches11.69 × 16.5410.12 × 14.33
Centimetres29.7 × 4225.7 × 36.4
Aspect ratio1:1.411:1.42
Area1247.4 cm²935.5 cm²

Which is bigger

A3, by 33.3% in area. A3 is 40 mm wider than JIS B4. A3 is 56 mm taller.

Printing one on the other

A JIS B4 page fits inside A3 whole — print it at 100% and you get a 20 mm border down each side and 28 mm top and bottom.

You wantSet the print scale toLeaves
A3 artwork on JIS B4 paper86.5%0 × 0.6 mm margin
JIS B4 artwork on A3 paper115.4%0.5 × 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: A3 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 0.6 mm of unwanted margin.

Frequently asked questions

What is the difference between A3 and JIS B4?

A3 is 297 × 420 mm and JIS B4 is 257 × 364 mm. A3 is the larger of the two by 33.3% in area.

Can I print A3 on JIS B4?

Not at full size. Scale it to 86.5% and it fits inside JIS B4 with 0 × 0.6 mm to spare.

Which is bigger, A3 or JIS B4?

A3 — 297 × 420 mm against 257 × 364 mm, which is 33.3% more area.

Related comparisons

A3 in full · JIS B4 in full · All size comparisons · All paper sizes