Code 128 Barcode Generator

The Code 128 standard covers all 128 ASCII characters, and this generator accepts the printable range: uppercase and lowercase letters, digits, spaces and punctuation. That flexibility is why it covers most identifiers a business actually uses, whether that is an alphanumeric SKU, a serial number with a letter prefix, or a purely numeric tracking code.

It shows up most often on SKUs, serial numbers and logistics labels precisely because it does not force the content into a narrow character set the way older formats do, and it stays compact even as the content gets longer.

Internally, Code 128 has three character subsets. Subset A handles uppercase letters, digits and control characters, subset B handles upper and lowercase letters, digits and punctuation, and subset C packs digits two at a time into a single symbol instead of one digit per symbol. A barcode can switch subsets partway through if that produces a shorter result, and this generator handles that switching automatically.

Subset C is what makes Code 128 the densest common 1D barcode for numeric content: two digits per symbol beats the one-character-per-symbol encoding that older formats like Code 39 use, and Code 39 also needs a wider gap between characters. The practical effect is that a given number of digits takes noticeably less label width in Code 128 than in Code 39.

GS1-128, sometimes still called UCC/EAN-128, is Code 128 combined with a special leading character and a defined set of application identifiers that structure the data into fields like batch number, expiry date or quantity. This generator produces plain Code 128 from the text you enter and does not add that leading character or parse application identifiers, so it is not a substitute for a dedicated GS1-128 label tool.

For printing, an SVG download stays sharp at any size, which suits label design software and large print runs, while PNG is simpler for quick use in office documents. Whichever format you use, leave a clear quiet zone around the bars and check that the label size matches your printer's resolution, since thin bars printed too small can blur into each other.