Module
A module is the narrowest building block of a barcode — the single unit width from which every bar, space, and pattern is constructed as whole-number multiples.
What You Need to Know
In linear symbologies, each bar and space is 1, 2, 3, or 4 modules wide. A Code 128 symbol character, for example, always spans exactly 11 modules divided into six elements. Because every element is a whole multiple of the module, the module acts as the "pixel size" of the printed symbol: if one module measures 0.33 mm, a 2-module bar prints 0.66 mm wide.
Modules matter because scanners sample the symbol in relative widths, not absolute ones. If printing or scaling makes module widths non-integer or uneven (for instance, by rasterizing to a canvas whose pixels do not align with module boundaries), the decode algorithm misjudges element ratios and the read fails. This is why vector (SVG) barcode output that preserves exact module proportions scans more reliably than carelessly resized raster images.
Where Module Applies
A high-density, variable-length linear barcode that encodes all 128 ASCII characters, and the backbone symbology of modern logistics.
Generate Code 128 →The 13-digit retail point-of-sale barcode used on consumer products worldwide outside North America.
Generate EAN-13 →The original 12-digit retail barcode of the United States and Canada, and direct ancestor of EAN-13.
Generate UPC-A →The classic self-checking alphanumeric barcode: 43 characters, simple structure, still everywhere in industry.
Generate Code 39 →A dense digits-only linear barcode that interleaves bar and space character pairs — logistics workhorse for numeric data.
Generate ITF (Interleaved 2 of 5) →