Convert Pixels per centimetre to Lines per inch

Convert Pixels per centimetre (px/cm) to Lines per inch (lpi) instantly and accurately.

Conversion Formula

lpi = px/cm × 2.54

About Pixels per centimetre

The pixel per centimetre (px/cm) is the metric counterpart of PPI, measuring pixel density per centimetre. EXIF assigns ResolutionUnit = 3 when resolution is stored in px/cm; Canon, Fujifilm, and Nikon cameras can output EXIF data in px/cm. GIMP stores and displays image resolution in px/cm in its XCF format and Image Properties dialog. DICOM (NEMA PS 3.3) stores spatial resolution as PixelSpacing in mm/pixel; a radiograph at 0.2 mm/px = 5 px/mm = 50 px/cm = 127 PPI. At 10×15 cm print size, a 12 MP image (4000×3000 px) prints at 4000/15 ≈ 266.7 px/cm ≈ 677 PPI - well above the ISO 12647-2 minimum of ≈ 118 px/cm (300 PPI). Since 1 inch = 2.54 cm exactly, 1 px/cm = 2.54 PPI exactly. 1 px/cm = 2.54 PPI = 10 px/dm = 100 px/m.

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.

Quick Reference Table

→ Full Image Resolution Converter