Convert Dots per point to Pixels per metre

Convert Dots per point (dot/pt) to Pixels per metre (px/m) instantly and accurately.

Conversion Formula

px/m = dot/pt × 2834.645669

About Dots per point

The dot per point (dot/pt) expresses output resolution relative to the PostScript point - exactly 1/72 inch, codified by Adobe in the PostScript Language Reference (1985). The Apple Macintosh 128K (1984) ran its built-in CRT at exactly 72 DPI, placing 1 dot per point - an intentional WYSIWYG design: a 12-point character on screen measured 12 pixels tall and printed at 12 points on the Apple LaserWriter. Device resolution milestones: Apple LaserWriter (1985) 300 DPI = 300/72 ≈ 4.17 dot/pt; HP LaserJet 4 (1992) 600 DPI ≈ 8.33 dot/pt; Linotronic 300 imagesetter (1985) 1270 DPI ≈ 17.64 dot/pt; Agfa Selectset 5000 at 2400 DPI = 33.33 dot/pt. TrueType and OpenType font hinting instructions align outline points to raster device pixels at the current dot/pt ratio. The CSS pt unit equals the PostScript point: 1 CSS pt = 1/72 CSS in = 4/3 CSS px at 1 dppx. 1 dot/pt = 72 DPI = 72 PPI.

About Pixels per metre

The pixel per metre (px/m) is the SI-coherent form of image resolution. Because 1 inch = 0.0254 m exactly (international inch, 1959), 1 PPI = 1/0.0254 ≈ 39.37 px/m and 1 px/m = 0.0254 PPI. EXIF (IEC 61966-3) stores resolution as pixels per inch (ResolutionUnit = 2) or pixels per centimetre (ResolutionUnit = 3); px/m is used when normalising to SI for scientific or GIS workflows. Satellite remote-sensing GSD is often given in metres per pixel (the inverse); WorldView-3 at 0.31 m/px panchromatic ≈ 3.23 px/m. An A4 document scanned at 300 PPI ≈ 11,811 px/m. 1 px/m = 0.0254 PPI ≈ 0.00254 px/cm.

Quick Reference Table

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