ARCH B in pixels
3600 × 5400 px
at 300 DPI, the print standard · ARCH B is 304.8 × 457.2 mm · 19.4 megapixels
ARCH B at every resolution
A sheet of paper has no pixel size of its own. It has a physical size — 304.8 × 457.2 mm, or 12 × 18 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 | 864 × 1296 | 1.1 MP | 3.2 MB | Screen only — visibly soft in print |
| 96 DPI | 1152 × 1728 | 2.0 MP | 5.7 MB | Screen only — visibly soft in print |
| 150 DPI | 1800 × 2700 | 4.9 MP | 14 MB | Drafts, internal documents, large-format viewed from a distance |
| 200 DPI | 2400 × 3600 | 8.6 MP | 25 MB | Acceptable for office printing |
| 300 DPI | 3600 × 5400 | 19.4 MP | 56 MB | The commercial print standard |
| 400 DPI | 4800 × 7200 | 34.6 MP | 99 MB | Fine detail and small type |
| 600 DPI | 7200 × 10800 | 77.8 MP | 222 MB | Line art, technical drawings, archival scanning |
| 1200 DPI | 14400 × 21600 | 311.0 MP | 890 MB | Archival and reproduction work |
What the file size means for ARCH B
At 300 DPI an uncompressed ARCH B is 56 MB, and at 600 DPI it is 222 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 56 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: 3600 px
Height: 5400 px
Resolution: 300 pixels/inch
Colour: CMYK for print, RGB for screen
Bleed: 3 mm on every edge → 3671 × 5471 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 B in pixels?
There is no single answer — it depends on the resolution. At the print standard of 300 DPI, ARCH B is 3600 × 5400 pixels. On screen at 72 DPI it is only 864 × 1296.
What resolution should an ARCH B document be?
300 DPI for anything going to a commercial printer, which makes the canvas 3600 × 5400 pixels. 150 DPI (1800 × 2700) 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 42 MB of file.
How big is an ARCH B file at 300 DPI?
About 56 MB uncompressed at 24-bit colour — 3600 × 5400 × 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 B PDF is usually tens of megabytes.
How many megapixels is ARCH B at 300 DPI?
19.4 megapixels. For comparison, ARCH B at 600 DPI is 77.8 MP — quadruple, because doubling the resolution doubles both dimensions.
ARCH B in millimetres, inches and points · All paper sizes · Screen resolutions