Code 128 Validator
Enter a value and we assess its character set, length and printability.
How to use in 3 steps
- 1
Enter the value
Type the text or digit string you want to encode as Code 128.
- 2
See the assessment
Review warnings about character set, length and printability.
- 3
Fix and generate
Resolve issues and turn it into a barcode directly with the [barcode generator](/en/barcode-generator).
Example input / output
Input
ABC-123 456
Output
Valid · mixed Set B/C · 10 chars · printable
Technical notes
Code 128 is a high-density 1D symbology that can encode all 128 ASCII characters (0-127). The tool checks whether your characters fall in that range; non-ASCII letters such as ş, ğ, ç cannot be encoded with standard Code 128.
Code 128 has three subsets A, B and C: Set A covers control characters and uppercase, Set B all printable ASCII, and Set C digit pairs only. Long digit-only data encoded with Set C packs two digits per module and noticeably shortens the barcode.
As length grows the barcode physically widens; very long values may not fit a narrow label or may scan poorly because the module width shrinks. The tool warns about length for practical printability.
GS1-128 is a variant that adds an Application Identifier structure on top of Code 128; if your value contains bracketed AIs, parse it with the GS1-128 parser. For invisible characters or space issues, use the barcode normalizer.
Frequently asked questions
Standard Code 128 supports only ASCII (0-127); letters like ş, ğ, ç, ı cannot be encoded. Avoid them or convert to ASCII equivalents.