Free Code 128B Barcode Generator — Full Printable ASCII Encoding

What Is Code 128B?

Code 128B is the most widely used encoding subset of Code 128. It covers the full printable ASCII range from 0x20 (space) to 0x7F (DEL), including all 26 uppercase letters, all 26 lowercase letters, all 10 digits, and the complete set of printable punctuation and symbols. Standardized within ISO/IEC 15417, Code 128B is the default subset assumed by most Code 128 implementations and is the correct choice for encoding any human-readable alphanumeric string that does not require ASCII control characters. If your data contains lowercase letters, Code 128B is required — neither Code 128A nor Code 128C can encode them.

• Complete Printable ASCII — Upper, Lower, Digits, Symbols

  Code 128B encodes every printable ASCII character: uppercase A–Z, lowercase a–z, digits 0–9, space, and all printable punctuation and special characters including !, @, #, $, %, ^, &, *, (, ), -, _, +, =, [, ], {, }, |, ;, :, ', ", ,, ., <, >, ?, /, \, `. This is the broadest character set among the three Code 128 subsets, making Code 128B the universal choice for mixed-case alphanumeric data.
• Required for Lowercase Letter Encoding

  Code 128B is the only Code 128 subset that can encode lowercase letters (a–z) as standard symbol characters without mode-switch overhead. If your barcode data includes any lowercase character — product names, URLs, reference codes with lowercase letters — Code 128B is the required subset. Code 128 auto mode automatically uses Subset B for lowercase characters, but Code 128B locks the entire barcode to Subset B encoding.
• Ideal for Mixed-Case Text and Human-Readable Labels

  Code 128B is the preferred format for labels where the encoded string is also displayed as human-readable text beneath the barcode. Mixed-case encoding allows product descriptions, reference numbers with lowercase suffixes, and URL paths to be encoded exactly as they appear in your system — preserving case sensitivity for applications that require it.
• Automatic Mod 103 Check Character

  Code 128B includes the standard Mod 103 check character computed and appended automatically by the encoder. The check character ensures that any single character substitution or barcode damage is detected and rejected by the scanner before the corrupted data reaches the host application.