Barcode generator

Product packaging, shelf and inventory labels, shipping waybills, books and periodicals, asset and equipment numbering, store price tags. For retail checkout prefer EAN-13 / EAN-8 / UPC-A - they carry a GS1 check digit that POS systems accept; for internal numbering CODE128 or CODE39 is enough. One caution: scanning successfully is not the same as being accepted by a supermarket system - trade barcodes must be registered with GS1 and issued a manufacturer prefix.

You can. Enter 12 digits for EAN-13 and the tool appends the check digit for you; enter all 13 and it checks yours, flagging a mismatch and giving the right value. Same for EAN-8 (7 / 8 digits), UPC-A (11 / 12) and ITF-14 (13 / 14). The rule is GS1 modulo-10 weighting: starting from the rightmost digit the weights alternate 3, 1; sum them and take (10 - sum mod 10) mod 10.

Check three things first. One, module width (the narrowest bar) should not go below 0.25 mm - on thermal receipt printers 0.3 mm or more, about 3 dots at 203 dpi and about 4 at 300 dpi. Two, leave a generous quiet zone around it, clear of text and table lines: the tool leaves 10 pixels by default, and when printing it is safer to scale up to roughly ten module widths. Three, contrast: dark bars on a light background, no glossy paper or coloured backgrounds. Scan distance tracks module width and bar height: with bars 0.3 mm or wider a handheld scanner reads reliably within 10 to 30 cm - to reach farther, scale the whole barcode up rather than only stretching its height.

Nothing is. Barcodes are drawn entirely in your browser (canvas and SVG), the content never leaves the machine and reloading clears it; batch takes up to 100 lines, one content per line, with PNG export packaged as a zip. Also note: a linear barcode merely encodes characters as wide and narrow bars - it carries no encryption and no anti-counterfeiting, so do not print sensitive data like passwords or ID numbers directly as a barcode.