The Complete Code 128 Barcode Guide
High-density, alphanumeric versatility. Master the world's most popular linear symbology for logistics and industrial inventory.
What is Code 128?
Code 128 is a high-density linear barcode symbology capable of encoding all 128 characters of the standard ASCII set. This includes uppercase letters, lowercase letters, numbers, and technical control characters. Its versatility and compactness have made it the global standard for logistics, shipping, and industrial inventory management.
Interactive Code 128 Generator
Use the tool below to generate high-resolution Code 128 barcodes. You can enter a single value or import a batch list from a CSV/Excel file for large-scale logistics operations.
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CODE128-LOGISTICS
Structural Anatomy
Every Code 128 symbol follows a strict physical structure defined by ISO/IEC 15417:
- Start Character: Identifies which subset (A, B, or C) the barcode begins with.
- Data Characters: The encoded information payload.
- Check Digit: Calculated using the Modulo 103 algorithm to verify scan integrity.
- Stop Character: A unique pattern signaling the end of the data.
Character Sets A, B, and C
To maximize density, Code 128 switches between three character subsets:
- Subset A: Ideal for capital letters, numbers, and technical ASCII control codes (like CR/LF).
- Subset B: The most common set, supporting mixed-case letters, numbers, and symbols.
- Subset C: Optimized for digits only. It packs two digits into a single symbol, making long numeric strings 50% more compact.