Convert Dots per inch to Lines per inch

Convert Dots per inch (DPI) to Lines per inch (lpi) instantly and accurately.

Conversion Formula

lpi = DPI × 1

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.

About Lines per inch

The line per inch (lpi) is the standard unit of halftone screen frequency in offset, flexographic, gravure, and screen printing. Each halftone cell varies in dot size to simulate grey tones; a 150 lpi screen on a 1200 DPI printer allocates 1200/150 = 8 printer dots per cell row, giving an 8×8 = 64-level grey matrix. Industry benchmarks: newsprint 85-100 lpi; magazines 133-175 lpi; fine-art offset 175-200 lpi; screen printing (textiles) 35-65 lpi. Rule of thumb: required DPI ≥ 1.5 × lpi for acceptable AM halftone; ≥ 2 × lpi for high quality - so 150 lpi offset needs at least 300 DPI raster data. As a dimensional quantity, 1 lpi = 1 PPI = 1 DPI; lpi designates screen frequency in print. 1 lpi = 1 PPI = 2.54 lpcm.

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