ARCH A in pixels
2700 × 3600 px
at 300 DPI, the print standard · ARCH A is 228.6 × 304.8 mm · 9.7 megapixels
ARCH A at every resolution
A sheet of paper has no pixel size of its own. It has a physical size — 228.6 × 304.8 mm, or 9 × 12 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 | 648 × 864 | 0.6 MP | 1.6 MB | Screen only — visibly soft in print |
| 96 DPI | 864 × 1152 | 1.0 MP | 2.8 MB | Screen only — visibly soft in print |
| 150 DPI | 1350 × 1800 | 2.4 MP | 7.0 MB | Drafts, internal documents, large-format viewed from a distance |
| 200 DPI | 1800 × 2400 | 4.3 MP | 12 MB | Acceptable for office printing |
| 300 DPI | 2700 × 3600 | 9.7 MP | 28 MB | The commercial print standard |
| 400 DPI | 3600 × 4800 | 17.3 MP | 49 MB | Fine detail and small type |
| 600 DPI | 5400 × 7200 | 38.9 MP | 111 MB | Line art, technical drawings, archival scanning |
| 1200 DPI | 10800 × 14400 | 155.5 MP | 445 MB | Archival and reproduction work |
What the file size means for ARCH A
At 300 DPI an uncompressed ARCH A is 28 MB, and at 600 DPI it is 111 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 28 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: 2700 px
Height: 3600 px
Resolution: 300 pixels/inch
Colour: CMYK for print, RGB for screen
Bleed: 3 mm on every edge → 2771 × 3671 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 ARCH A in pixels?
There is no single answer — it depends on the resolution. At the print standard of 300 DPI, ARCH A is 2700 × 3600 pixels. On screen at 72 DPI it is only 648 × 864.
What resolution should an ARCH A document be?
300 DPI for anything going to a commercial printer, which makes the canvas 2700 × 3600 pixels. 150 DPI (1350 × 1800) 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 21 MB of file.
How big is an ARCH A file at 300 DPI?
About 28 MB uncompressed at 24-bit colour — 2700 × 3600 × 3 bytes. Compression brings that down a great deal for flat artwork and very little for a photograph, which is why a print-ready ARCH A PDF is usually tens of megabytes.
How many megapixels is ARCH A at 300 DPI?
9.7 megapixels. For comparison, ARCH A at 600 DPI is 38.9 MP — quadruple, because doubling the resolution doubles both dimensions.
ARCH A in millimetres, inches and points · All paper sizes · Screen resolutions