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Free Online CODE 128A Barcode Generator

CODE128A Mode

Code 128 Set A targets the ASCII range from NUL through underscore, making it suitable for uppercase identifiers and legacy control-character payloads. Validate your input against Set A rules and export barcode images for specialized label workflows.

1. Enter barcode data

0 entries · Blank lines ignored · Duplicate values detected

2. Choose barcode settings

Barcode preview

Download settings

What is a CODE128A barcode?

CODE128A is the Code 128 subset that maps ASCII values 0 through 95, including control characters and uppercase-friendly symbols. Label systems that pin the encoder to Set A use it when data includes function codes, fixed uppercase fields, or legacy mainframe character mappings that cannot shift into Set B or C.

Recommended generator settings

These defaults work well for preview and download. Adjust to match your label template or scanner tests.

Bar width Start at 2; increase only if scans fail at your print size
Height 100 px or taller for warehouse and logistics labels
Quiet zone Keep the default margin unless your spec defines a different quiet zone
Readable text Leave enabled when operators verify values manually
Output format PNG for design files; JPEG for documents and quick sharing

Practical examples

  • CT-001
  • WAREHOUSE-A1
  • CTRL-REF-009
  • BIN-UPPER-22

When should you use CODE128A?

  • Label templates that explicitly require Code 128 Subset A encoding
  • Uppercase-only identifiers in warehouse and manufacturing systems
  • Legacy integrations that embed control characters in barcode data
  • Testing Set A compatibility before deploying new scanner firmware

Limitations and common mistakes

Use CODE128B for mixed-case printable text or CODE128C for all-numeric data at higher density. General-purpose labels usually work fine with standard CODE128 auto-switching.

  • Trimming quiet zones when cropping the image for a label layout.
  • Scaling the barcode unevenly so bar width ratios no longer match the generated image.

Related formats

CODE128A vs CODE128B

Format Best for Supported data Key difference
Code 128 Warehouse and inventory labels where the encoded value mixes letters and numbers Printable ASCII (codes 33–126) Letters, digits, and common punctuation within printable ASCII.
Code 128 Set B Mixed-case SKU or order references on packing slips and pick lists Printable ASCII (space through ~, codes 32–126) Printable ASCII from space through tilde; supports lowercase and mixed case.
Code 128 Set C Long numeric shipment or container references on warehouse labels Digits 0–9 only An even-length string of 0–9 encoded two digits at a time.

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Printing and scanning notes

Printing

  • Confirm your label spec mandates Set A before printing production quantities.
  • Keep quiet zones intact; control-character payloads still need standard margins.
  • Print human-readable text when operators must verify uppercase-only fields.

Scanning

  • Verify scanners are configured for Code 128 Subset A if your data includes control codes.
  • Test with the same scanner model used on the production line.
  • Compare scan results against the source value to catch charset mismatches early.

Frequently asked questions

Standard CODE128 can switch between sets A, B, and C. CODE128A locks encoding to Subset A (ASCII 0–95).

Lowercase letters fall outside Set A. Use CODE128B or standard CODE128 for mixed-case text.

Some ERP or WMS exports pin the symbology to Subset A for compatibility with fixed-width control fields.

Yes, the Code 128 modulo-103 check character is calculated automatically.

Characters above ASCII 95 (such as lowercase letters or many symbols) are not valid in Set A.

Yes. Enter one Set A–compatible value per line to create multiple images.