A3 in pixels
3508 × 4961 px
at 300 DPI, the print standard · A3 is 297 × 420 mm · 17.4 megapixels
A3 at every resolution
A sheet of paper has no pixel size of its own. It has a physical size — 297 × 420 mm, or 11.69 × 16.54 inches — and a pixel count only appears once you choose how many pixels go in each inch.
| Resolution | Pixels | Megapixels | Uncompressed 24-bit | Use |
|---|---|---|---|---|
| 72 DPI | 842 × 1191 | 1.0 MP | 2.9 MB | Screen only — visibly soft in print |
| 96 DPI | 1123 × 1587 | 1.8 MP | 5.1 MB | Screen only — visibly soft in print |
| 150 DPI | 1754 × 2480 | 4.3 MP | 12 MB | Drafts, internal documents, large-format viewed from a distance |
| 200 DPI | 2339 × 3307 | 7.7 MP | 22 MB | Acceptable for office printing |
| 300 DPI | 3508 × 4961 | 17.4 MP | 50 MB | The commercial print standard |
| 400 DPI | 4677 × 6614 | 30.9 MP | 89 MB | Fine detail and small type |
| 600 DPI | 7016 × 9921 | 69.6 MP | 199 MB | Line art, technical drawings, archival scanning |
| 1200 DPI | 14031 × 19843 | 278.4 MP | 797 MB | Archival and reproduction work |
What the file size means for A3
At 300 DPI an uncompressed A3 is 50 MB, and at 600 DPI it is 199 MB — four times as much, because doubling the resolution doubles both dimensions. That squaring is the reason large formats become unwieldy so quickly: the same 300 DPI that produces a manageable file at small sizes produces 50 MB here.
If a file is going to a printer, ask what they want before choosing. 300 DPI is the safe default and 150 is often enough for anything read from more than arm's length.
Setting up the canvas
Width: 3508 px
Height: 4961 px
Resolution: 300 pixels/inch
Colour: CMYK for print, RGB for screen
Bleed: 3 mm on every edge → 3579 × 5031 pxThe bleed figure is the one people forget: artwork that runs to the edge must extend 3 mm past it on all four sides, so the working canvas is larger than the finished sheet.
Frequently asked questions
What is A3 in pixels?
There is no single answer — it depends on the resolution. At the print standard of 300 DPI, A3 is 3508 × 4961 pixels. On screen at 72 DPI it is only 842 × 1191.
What resolution should an A3 document be?
300 DPI for anything going to a commercial printer, which makes the canvas 3508 × 4961 pixels. 150 DPI (1754 × 2480) is acceptable for a draft or an internal document. Large formats read from a distance can go lower — a poster viewed from two metres looks sharp at 150 DPI, and dropping to it here saves 37 MB of file.
How big is an A3 file at 300 DPI?
About 50 MB uncompressed at 24-bit colour — 3508 × 4961 × 3 bytes. Compression brings that down a great deal for flat artwork and very little for a photograph, which is why a print-ready A3 PDF is usually tens of megabytes.
How many megapixels is A3 at 300 DPI?
17.4 megapixels. For comparison, A3 at 600 DPI is 69.6 MP — quadruple, because doubling the resolution doubles both dimensions.
A3 in millimetres, inches and points · All paper sizes · Screen resolutions