Print files
A3 Print Size in Pixels at 300 DPI
A3 measures 297×420 mm — 3508×4961 pixels at 300 DPI. It shares its ratio with A4, so an A3 crop scales down to A4 cleanly, as long as you have the pixels for it.
Direct answer
A3 at 300 DPI is 3508×4961 pixels in portrait orientation. To get there yourself: divide 297 mm and 420 mm by 25.4, then multiply by 300. Landscape A3 is 4961×3508. A4 shares the same ratio at 2480×3508. Don’t stretch an 11×17 file (3300×5100) or an 11×14 file to fill an A3 listing — export the millimetres you actually sell.
UK and EU Etsy shops list A3 next to A4 the same way US shops list 16×20 next to 8×10. But unlike 16×20 and 8×10, A3 and A4 share the exact same shape, so you can reuse one composition across both. You still can’t stretch a 2480-pixel A4 file into a sharp A3, though.
US tabloid paper (11×17) is what most people confuse with A3. They’re close, but not identical — see our 11×17 guide for the difference.
- 1
Enter 297 × 420 mm
Not 11×17 inches — they’re different shapes.
- 2
Crop around the subject
ISO height differs from a standard 2:3 poster.
- 3
Confirm 3508×4961 pixels
Or match the shop template’s exact pixel count.
- 4
Save at 300 DPI
JPG for photos, PNG for type.
The full ISO A ladder at 300 DPI
A5 is 1748×2480. A4 is 2480×3508. A3 is 3508×4961. A2 is 4961×7016. They all share the same ratio, so you can always scale down freely, but only scale up if the original has the pixels to support it.
A5
A4 · 2480×3508 px
A3
| Size | Millimetres | Pixels |
|---|---|---|
| A4 | 210 × 297 | 2480 × 3508 |
| A3 | 297 × 420 | 3508 × 4961 |
| A2 | 420 × 594 | 4961 × 7016 |
A3 vs 11×17 vs 12×18: three different shapes
11×17 comes out to 3300×5100 pixels, taller than A3’s ratio. 12×18 is 2:3, or 3600×5400 pixels. A3 is 1:√2. That’s three separate crops, not one file resized three ways. If you ship to both the US and EU, export A3 and 12×18 separately from the same focal point.
Export A3 straight from Reopic
Open Studio and add 297 × 420 mm as a custom size, then hit Export Artwork. Pair it with 210 × 297 mm for A4 in the same session. Pro ($33 lifetime) makes batch exports like this painless.
Most home printers can’t handle A3
Most home inkjets max out at A4. Buyers who order a digital A3 file need an A3 printer or a copy shop — say so in your listing. “Fit to A4” will shrink their poster and hand you a one-star review that isn’t really about your file.
FAQ: A3 print size pixels 300 DPI
How many pixels is A3 at 300 DPI?+
3508×4961 pixels in portrait orientation.
Is A3 the same as 11x17?+
No. 11×17 is 3300×5100 pixels. A3 is 297×420 mm, or 3508×4961 pixels.
Can I enlarge an A4 file to A3?+
Only if the original file still has A3-level pixels. An A4-sized export (2480×3508) becomes 150 DPI once stretched to A3.
Is A3 exactly twice the size of A4?+
Twice the area, same shape. Two A4 sheets tile perfectly into one A3.
