Code 39 Barcode Generator

Code 39 is one of the oldest alphanumeric barcodes, and still a requirement in plenty of places. Automotive and defence supply chains, older warehouse systems, some ID badges and many legacy label templates expect it. It encodes uppercase letters, digits, space and a few symbols, and every character is self-contained, which makes it very tolerant of low-quality printers. The trade-off is width: Code 39 is much wider than Code 128 for the same data. Type your value and QRPebble converts letters to uppercase, rejects unsupported characters and keeps it under 43 characters. Use Code 39 when a system or customer specifically asks for it.

Design options
Fill in the form to preview your code.

How to make it

  1. Type the value in the Data field; lowercase letters are converted to uppercase.
  2. Don't type the * start/stop characters; the renderer adds them.
  3. Check the preview width fits your label; Code 39 grows quickly with each character.
  4. Download and scan-test with the reader used by the receiving system.

What gets encoded

Code 39 supports 43 characters: A–Z, 0–9, space and - . $ / + %. Each symbol is framed by an asterisk start/stop character, which scanners don't include in the output. This generator doesn't add the optional mod-43 check digit. If your customer's specification requires one, confirm with them before printing. 'Full ASCII' Code 39, which represents lowercase letters with character pairs, isn't supported. Most handheld scanners read Code 39 by default, though a few have it disabled and need it switched on.

Where people use it

  • Automotive (AIAG) and defence part labels
  • Legacy warehouse and manufacturing systems
  • Employee ID badges and access cards
  • Equipment labels printed on dot-matrix or low-resolution printers

Tips before you print

  • If you have a choice, Code 128 fits the same data in far less space; use Code 39 when required.
  • Keep the wide-to-narrow bar ratio intact. Stretching the image in one direction only can break scanning.
  • Leave at least 10 module widths of clear space on each side.

FAQ

Why can't I use lowercase letters?

Standard Code 39 has no lowercase characters. QRPebble converts them to uppercase automatically.

Should I type the asterisks?

No. The * start and stop characters are added by the renderer, and typing them is rejected.

Does this add a Code 39 check digit?

No. The optional mod-43 check digit isn't added, so check your customer's specification if they require it.

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