Size comparison
A4 vs A5
A4 (210 × 297 mm) is exactly twice the area of A5 (148 × 210 mm). Fold an A4 sheet in half along its long edge and you get a perfect A5. Both share the ISO 216 aspect ratio of 1 : √2, which means designs scale between them without distortion at exactly 70.7 % (down) or 141.4 % (up).
Both sheets drawn to the same scale. The dashed line is the A4 half-fold that produces A5.
Side-by-side dimensions
| Property | A4 | A5 |
|---|---|---|
| Millimetres | 210 × 297 | 148 × 210 |
| Centimetres | 21.0 × 29.7 | 14.8 × 21.0 |
| Inches | 8.27 × 11.69 | 5.83 × 8.27 |
| Pixels @ 300 DPI | 2480 × 3508 | 1748 × 2480 |
| Pixels @ 96 DPI | 794 × 1123 | 559 × 794 |
| Area | 623.7 cm² | 310.8 cm² |
| Aspect ratio | 1 : √2 (≈ 1 : 1.414) — identical for both | |
| Reference page | Full A4 guide | Full A5 guide |
Choose A4 when…
- The document is text-dense: reports, contracts, CVs, essays
- It will be read at a desk or filed in standard folders
- You need room for tables, charts or technical drawings
- It goes on a notice board and is read from ~1 m away
- The recipient will print it themselves (A4 is the universal home format)
Choose A5 when…
- It is handed out or posted through letterboxes: flyers, leaflets
- Cost matters — two A5s per A4 sheet halves the paper bill
- It is a booklet, programme, zine or menu meant to be held
- The message is short: one headline, one image, one call to action
- It should fit in a bag, pocket or greeting-card envelope (C5)
Scaling designs between A4 and A5
Because the aspect ratio is identical, no cropping is ever needed. Going from A4 down to A5 is a uniform 70.7 % scale; going up is 141.4 %. Two things to check after scaling:
- Type size: 10 pt body text at A4 lands at ~7 pt on A5 — below comfortable reading size. Bump body copy back up to 9–10 pt after scaling down.
- Bleed is absolute, not relative: the 3 mm bleed does not scale. An A5 export still needs a fresh 3 mm on each side (154 × 216 mm total), not the scaled-down remnant of the A4 bleed.
Frequently asked questions
Which is bigger, A4 or A5?
A4 is bigger. A4 measures 210 × 297 mm; A5 measures 148 × 210 mm. A4 has exactly twice the area of A5 — folding an A4 sheet in half along its long edge produces an A5 sheet.
Is A5 exactly half of A4?
Yes, exactly. This is by design: ISO 216 defines every A-series size as half of the size above it, cut along the long edge, with the 1:√2 aspect ratio preserved at every step.
Can I print an A4 design at A5 size?
Yes, cleanly. Because both share the same 1:√2 aspect ratio, an A4 layout scales down to A5 at about 70.7% with no cropping and no distortion. Text becomes proportionally smaller, so check that body copy is still readable (10 pt at A4 becomes ~7 pt at A5).
Should my flyer be A4 or A5?
A5 for handouts, door-drops and anything people carry: cheaper (two per A4 sheet), easier to hold, fits letterboxes. A4 for information-dense flyers, notice boards and anything read at arm's length on a wall or counter. If in doubt for street distribution, A5 wins.
Which is better for a booklet — A4 or A5?
A5 booklets are the standard: they are made from A4 sheets folded in half, which every print shop handles cheaply. A4 booklets need A3 sheets folded, cost more, and feel more like reports than reading material.
What is the exact scale factor between A4 and A5?
Scaling A4 down to A5 is ×0.707 (1/√2 ≈ 70.7%). Scaling A5 up to A4 is ×1.414 (√2 ≈ 141.4%). These are the same scale factors used between any two adjacent A-series sizes.