Convert Dots per centimetre to Pixels per millimetre

Convert Dots per centimetre (dpcm) to Pixels per millimetre (px/mm) instantly and accurately.

Conversion Formula

px/mm = dpcm × 0.1

About Dots per centimetre

The dot per centimetre (dpcm) is the metric equivalent of DPI, defined as a CSS resolution unit in the W3C CSS Images Level 3 specification alongside dpi and dppx. A 96 DPI reference screen (CSS Media Queries Level 4 reference device) corresponds to 96/2.54 ≈ 37.795 dpcm. ITU-T T.4 (Group 3 facsimile, 1980) defines scan line density in metric units: standard resolution 3.85 lines/mm = 38.5 dpcm; fine resolution 7.7 lines/mm = 77 dpcm. ITU-T T.85 (JBIG compression) standardised these metric resolutions for cross-border interoperability. ISO 216 A4 scanned at 77 dpcm fine fax resolution yields 1617 pixels across page width. The CSS specification recommends dppx over dpcm for screen media queries, reserving dpcm for print stylesheets targeting metric-resolution printers. 1 dpcm = 2.54 DPI = 2.54 PPI exactly (since 1 in = 2.54 cm). 1 dpcm = 0.1 dot/mm.

About Pixels per millimetre

The pixel per millimetre (px/mm) is the resolution unit of precision in machine vision, flatbed scanning, and microscopy, where working distances are in millimetres. Industrial camera datasheets (Basler acA5472-17um, FLIR BFS-U3-200S6M-C) specify resolution in px/mm at defined field widths; a 20 MP sensor over a 100 mm field resolves 54.96 px/mm. ISO 12654 (archival scanning) specifies minimum 8 px/mm (≈ 200 PPI) for standard digitisation and 24 px/mm (≈ 600 PPI) for fine-detail originals. Digital pathology: Leica Aperio GT450 at 40× magnification achieves ≈ 4,405 px/mm. CMOS sensor pixel pitch has shrunk from 7.4 µm/px (≈ 135 px/mm, mid-2000s) to 0.64 µm/px (≈ 15,625 px/mm) for smartphone sensors in 2024. Since 1 in = 25.4 mm exactly, 1 px/mm = 25.4 PPI exactly. A 300 PPI photo print = 300/25.4 ≈ 11.81 px/mm.

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