EAN-13 barcode generator
Thirteen digits: a GS1 company prefix, your item reference, and a check digit calculated from the other twelve. Enter twelve and the last is worked out for you.
How to make a ean-13 barcode
The check digit uses alternating weights of 1 and 3 across the twelve digits, summed, then subtracted from the next multiple of ten. That construction catches every single-digit error and most transpositions, which is why a mis-keyed barcode almost always fails rather than silently scanning as a different product. The part a generator cannot help with: the number itself must come from GS1, who allocate company prefixes. Inventing a number that happens to have a valid check digit produces a barcode that scans perfectly and may collide with a real product somewhere: fine for internal use, not for retail.
Questions
Weight the twelve digits alternately 1 and 3, sum them, and subtract from the next multiple of ten.
For internal use, yes. For retail, no — the prefix must come from GS1 or you risk colliding with a real product.
UPC-A is twelve digits and is EAN-13 with a leading zero. The bars are the same pattern.
Almost always resolution or contrast. Print from the SVG rather than scaling a PNG, keep the quiet zone clear on both sides, and use black on white; a coloured or shiny background defeats most scanners.
Nominal is 37.29 × 25.93 mm. Down to 80 percent is generally safe; below that scanning gets unreliable.