Convert Pixels per metre to Pixels per inch

Convert Pixels per metre (px/m) to Pixels per inch (PPI) instantly and accurately.

Conversion Formula

PPI = px/m × 0.0254

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.

About Pixels per inch

The pixel per inch (PPI) is the universal standard for digital image resolution, defining how many pixels occupy one linear inch in a digital image, sensor, or display. Formally referenced in ISO 12232 (digital still cameras) and EXIF/TIFF (tags 0x011A/0x011B), PPI is both a capture parameter (scanner/sensor density) and a display characteristic. Display milestones: Macintosh 128K (1984): 72 PPI; Apple iPhone 4 Retina (2010): 326 PPI - above the human perceptual threshold at 25 cm; iPhone 15 Pro (2023): 460 PPI. Print benchmarks: 150 PPI (large-format, 1 m viewing); 300 PPI (standard offset, ISO 12647-2); 400-600 PPI (fine-art Giclée). EXIF stores PPI as unsigned RATIONAL; the historical default is 72/1, a carry-over from the original Macintosh screen standard. 1 PPI = 1/0.0254 px/m ≈ 39.37 px/m = 2.54 px/cm.

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