A3 vs ARCH B
| A3 | ARCH B | |
|---|---|---|
| Millimetres | 297 × 420 | 304.8 × 457.2 |
| Inches | 11.69 × 16.54 | 12 × 18 |
| Centimetres | 29.7 × 42 | 30.5 × 45.7 |
| Aspect ratio | 1:1.41 | 1:1.5 |
| Area | 1247.4 cm² | 1393.5 cm² |
Which is bigger
ARCH B, by 11.7% in area. ARCH B is 7.8 mm wider than A3. ARCH B is 37.2 mm taller.
Printing one on the other
A A3 page fits inside ARCH B whole — print it at 100% and you get a 3.9 mm border down each side and 18.6 mm top and bottom.
| You want | Set the print scale to | Leaves |
|---|---|---|
| A3 artwork on ARCH B paper | 102.6% | 0 × 26.2 mm margin |
| ARCH B artwork on A3 paper | 91.9% | 17 × 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 ARCH B is 1:1.5. 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 26.2 mm of unwanted margin.
Frequently asked questions
What is the difference between A3 and ARCH B?
A3 is 297 × 420 mm and ARCH B is 304.8 × 457.2 mm. ARCH B is the larger of the two by 11.7% in area.
Can I print A3 on ARCH B?
Yes, at 100% — A3 is smaller on both edges, so it lands inside ARCH B with a border all round.
Which is bigger, A3 or ARCH B?
ARCH B — 304.8 × 457.2 mm against 297 × 420 mm, which is 11.7% more area.
A3 in full · ARCH B in full · All size comparisons · All paper sizes