Convert Pixels per inch to Dots per inch

Convert Pixels per inch (PPI) to Dots per inch (DPI) instantly and accurately.

Conversion Formula

DPI = PPI × 1

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.

About Dots per inch

The dot per inch (DPI) is the standard resolution metric for printed output, specifying how many individual ink or toner dots a printing device places per linear inch. Unlike a pixel, a printed dot is a physical deposit of ink variable in size and subject to dot gain (ink spread into substrate). Inkjet photo printers: Epson SureColor SC-P900 up to 5760 DPI; HP DesignJet Z9+Pro at 2400 DPI. Laser printers: HP LaserJet standard 600 DPI; enterprise class 1200 DPI. Offset CTP plate imaging: 2400-3600 DPI. Rule of thumb: required DPI ≥ 1.5 × LPI for acceptable halftone; ≥ 2 × LPI for high quality - a 175 lpi magazine job needs ≥ 350 DPI raster data. Thermal dye-sublimation printers achieve continuous-tone output at 300 DPI because dye diffuses to fill each cell. As a dimensional unit, 1 DPI = 1 PPI; DPI implies physical print output. 1 DPI = 2.54 dots/cm = 25.4 dots/mm.

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