A3 paper measures 297 × 420 mm. Its pixel dimensions change with PPI; the physical trim size does not.
A3 measures exactly 297 × 420 mm (29.7 × 42 cm), or approximately 11.69 × 16.54 inches. At 300 PPI, portrait A3 rounds to 3508 × 4961 pixels.
300 PPI: 3508 × 4961 px · ISO 216 trimPortrait values are rounded to the nearest whole pixel after converting the native physical dimensions.
| PPI | Width | Height | Use context |
|---|---|---|---|
| 72 | 842 px | 1191 px | Layout or screen reference |
| 96 | 1123 px | 1587 px | Layout or screen reference |
| 150 | 1754 px | 2480 px | Print / distance dependent |
| 240 | 2806 px | 3969 px | Print / distance dependent |
| 300 | 3508 px | 4961 px | Detailed print target |
| 600 | 7016 px | 9921 px | Detailed print target |
A3 is 1754 × 2480 px at 150 PPI, 2806 × 3969 px at 240 PPI and 3508 × 4961 px at 300 PPI. Confirm the target with the print provider.
Check an actual imageFolding A3 in half along its long edge produces A4. Both formats keep the ISO 1:√2 aspect ratio, so layouts can scale proportionally.
Compare A4Adding 3 mm on every edge creates a 303 × 426 mm artwork canvas, which rounds to 3579 × 5031 pixels at 300 PPI.
Calculate another marginA3 is a common bridge between office documents and wall graphics. Designers use it for menu sheets, classroom diagrams, proof sheets, folded A4 spreads and short-distance posters where A4 would feel crowded but A2 would be unnecessarily large.
An A3 sheet folds to A4 while keeping the ISO proportion. That makes it useful for a two-page A4 spread or a folded handout, but the fold and binding area need their own safe margin. A full-page A4 layout should be intentionally scaled or reflowed rather than simply centred on A3.
At 300 PPI, A3 needs 3508 × 4961 pixels before bleed. Small text and detailed diagrams can justify that dense target; a simple poster viewed farther away may use a lower provider-approved value. Vector type and logos should remain vector when the workflow allows it.
For this A3 example, the printer requests 3 mm bleed on every edge and a 5 mm safe margin inside trim. The artwork canvas becomes 303 × 426 mm, or 3579 × 5031 pixels at 300 PPI. The protected region is 287 × 410 mm. These are example production requirements, not part of the paper standard.
Set the trim before placing the layout, extend the real background into bleed, and keep faces, lettering and other essential content inside the provider’s safe margin. A raster canvas and a PDF with page boxes describe the same physical job differently; do not scale all artwork simply to include an export border.
Recalculate with your printer’s exact marginsA3 identifies the final physical format. Bleed expands the artwork beyond that edge; a safe margin moves important content inward. Those extra values depend on the print provider.
Calculate bleed and safe areaUse the source pixels, final orientation and intended crop for small posters, menus and folded A4 spreads; then confirm the required PPI with the provider.