A4 vs A5
A5 is exactly half of A4: fold an A4 sheet across the long edge and you have two A5. Same 1 : √2 shape, so A5 scales up to A4 at 141% and A4 down to A5 at 71%, edge to edge.
Compare a Different Pair
A4 and A5, Side by Side
| A4 | A5 | Difference | |
|---|---|---|---|
| Millimetres | 210 × 297 | 148 × 210 | 62 × 87 mm |
| Inches | 8.27 × 11.69 | 5.83 × 8.27 | 2.44 × 3.43 in |
| Centimetres | 21.0 × 29.7 | 14.8 × 21.0 | |
| Area | 0.0624 m², 62,370 mm² | 0.0311 m², 31,080 mm² | 2.01× |
| Aspect ratio | 1 : 1.414 (√2) | 1 : 1.419 (√2) | same |
What Is Lost Printing One on the Other
At 100% scale, both centred, nothing resized. A positive figure on the wider or taller side is cropped; on the other it is a blank margin.
| Axis | Gap | A4 onto A5 | A5 onto A4 |
|---|---|---|---|
| Width | 31 mm (1.22 in) each side | A4 loses it | blank band |
| Height | 43.5 mm (1.71 in) each end | A4 loses it | blank band |
Scale-to-Fit Percentages
The figure to type into a printer or PDF dialog to scale one to fit inside the other:
| A5 to fit A4 | 141% | fills the sheet, nothing cropped |
|---|---|---|
| A4 to fit A5 | 71% | fills the sheet, nothing cropped |
Both are one halving apart on the 1 : √2 series, so these are the copier presets and nothing is distorted or lost.
Which Should You Use?
Use A4 for documents that go through a printer or a filing system, and A5 for anything folded, bound or handed out: notepads, flyers, order pads, short booklets.
Beyond the Measurements
Envelopes: A4 fits C4, C5, DL; A5 fits C5, C6.
An A4 letter folded in three drops into a DL envelope and posts at the standard letter rate. Folded once it fits C5; flat and unfolded it needs a C4, which Royal Mail rates as a large letter up to 100 g. In the US an A4 sheet in a 9 x 12 in envelope goes as a flat.
Worth Knowing
A4 and A5 are the pair people mix up least once they know the trick: one is literally the other folded in half. The real decision is almost never about the paper and almost always about what happens next. If it gets stapled into a booklet, drafting at A4 and printing two-up on A4 is the cheap route to A5. If it gets posted, A5 folded once fits a C6 and A4 folded in three fits a DL. Design at the size the reader holds, then work back to the sheet on the printer.
Frequently Asked Questions
Is A4 bigger than A5?
A4 is bigger. It is 210 × 297 mm against 148 × 210 mm for A5, about 2.01 times the area.
What is the difference between A4 and A5?
A5 is exactly half of A4: fold an A4 sheet across the long edge and you have two A5. Same 1 : √2 shape, so A5 scales up to A4 at 141% and A4 down to A5 at 71%, edge to edge.
Can you print A5 on A4?
Yes, cleanly. Set the printer to scale A5 to 141% and it fills A4 edge to edge with nothing lost.
✓ Dimensions per the standards on the A4 and A5 pages. Differences and scale factors computed. Reviewed . Editorial Process →