A3, A2, A1 Poster Sizes in Pixels (300 DPI Chart)
Selling posters to international buyers means the ISO A series, not inches. Here are the exact pixel dimensions for each A size at 300 DPI.
Updated
- Exact pixel dimensions for A-series poster sizes at 300 DPI — A5 through A1 — for international printable and poster sellers.
- 3508×4961 pixels.
- Yes — all A sizes share the same ~1:1.414 ratio, so one correctly-proportioned file prints A5 through A1.
International buyers frame in the ISO A series (the A4-paper family), not US inch sizes. If you sell posters or printable art abroad, these are the dimensions you build to.
A-series at 300 DPI
A6 and A5 in inches and pixels
| Size | Millimetres | Inches | Pixels @ 300 DPI |
|---|---|---|---|
| A6 | 105 × 148 mm | 4.13 × 5.83 in | 1240 × 1748 px |
| A5 | 148 × 210 mm | 5.83 × 8.27 in | 1748 × 2480 px |
| A4 | 210 × 297 mm | 8.27 × 11.69 in | 2480 × 3508 px |
Each A size is the one above it folded in half, so the ratio stays 1:√2 all the way down.
| Size | Millimetres | Inches | Pixels @ 300 DPI |
|---|---|---|---|
| A5 | 148×210 | 5.8×8.3 | 1748×2480 |
| A4 | 210×297 | 8.3×11.7 | 2480×3508 |
| A3 | 297×420 | 11.7×16.5 | 3508×4961 |
| A2 | 420×594 | 16.5×23.4 | 4961×7016 |
| A1 | 594×841 | 23.4×33.1 | 7016×9933 |
The nice property of A sizes
Every A size is the same aspect ratio (≈1:1.414). Fold an A-size sheet in half and you get the next size down. That means one file at the right proportion prints every A size — you just need enough pixels for the largest one you list. To also cover A1, build at 7016×9933 px; smaller sizes downscale cleanly from there.
A-series vs US sizes
A4 is not US Letter — it's a different shape (taller and narrower). If you sell to both markets, offer an A-series file and a US Letter/inch file. Full comparison.
Building the file
Because all A sizes share a ratio, one master covers them — but at 300 DPI, A1 needs nearly 10,000 px on the long edge, which is a large file. Export as a high-quality JPG to stay manageable, and split ZIPs if you exceed Etsy's 20 MB limit.
One image, every A size
Drop your art into the free Ratio-Pack Generator and it produces an ISO-A master alongside the US ratios, tags everything 300 DPI, and reports the largest A size your file prints cleanly — so international buyers get a file that fits their frames.
Ratio-Pack Generator
Turn one image into every print ratio buyers ask for — 300 DPI, cropped in your browser. Free, instant, nothing uploads.