A3 vs A4

Q: Can I print A3 on A4?

Not at full size. Scale it to 70.7% and it fits inside A4 with 0 × 0 mm to spare.

	A3	A4
Millimetres	297 × 420	210 × 297
Inches	11.69 × 16.54	8.27 × 11.69
Centimetres	29.7 × 42	21 × 29.7
Aspect ratio	1:1.41	1:1.41
Area	1247.4 cm²	623.7 cm²

Which is bigger

A3 and A4 are one step apart in the A series, so one is exactly twice the other. Two A4 sheets side by side make an A3, and folding an A3 in half across its long edge gives two A4. That is what the series is for, and it is why the scale factors below come out at 70.7% and 141.4% — one over the square root of two, and the square root of two.

A3 is 87 mm wider than A4. A3 is 123 mm taller.

Printing one on the other

A A4 page fits inside A3 whole — print it at 100% and you get a 43.5 mm border down each side and 61.5 mm top and bottom.

You want	Set the print scale to	Leaves
A3 artwork on A4 paper	70.7%	0 × 0 mm margin
A4 artwork on A3 paper	141.4%	0 × 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 A4?

A3 is 297 × 420 mm and A4 is 210 × 297 mm. A3 is the larger of the two by 100% in area.

Can I print A3 on A4?

Not at full size. Scale it to 70.7% and it fits inside A4 with 0 × 0 mm to spare.

Which is bigger, A3 or A4?

A3 — 297 × 420 mm against 210 × 297 mm, which is 100% more area.

Related comparisons

A3 in full · A4 in full · All size comparisons · All paper sizes