Codabar Barcode Generator – The Classic Barcode for Blood Banks and Libraries

What Is a Codabar Barcode?

Codabar is a linear barcode symbology developed in 1972 by Pitney Bowes. It is also known by several other names depending on the industry: NW-7 (in Japan), USD-4 (Uniform Symbology Description 4), Code 2 of 7, and Rationalized Codabar. Despite its age, Codabar remains in active use in several specialised industries that have built their infrastructure around it.

Codabar is a self-checking symbology – each character is independently verifiable, making it resistant to single-character substitution errors without requiring a check digit. It uses four different bar widths and four space widths to encode 16 characters: digits 0–9, six special characters (- $ : / . +), and four start/stop characters (A, B, C, D).

The start and stop characters are unique to Codabar among common symbologies. They allow different applications to use different letter pairs (A/A, A/B, A/C, etc.) to identify the type of data encoded, which was particularly useful before standard data identifiers existed.

Technical Specifications

The choice of start/stop characters carries meaning in some applications. For example, the American Blood Commission uses A/A or A/D pairs, while FedEx airbills use specific letter combinations to indicate the type of tracking number.

Common Use Cases for Codabar

• • Blood banks: The ISBT (International Society of Blood Transfusion) historically used Codabar for blood bag identification. ISBT 128 has since replaced it in many facilities, but legacy Codabar systems persist in some blood banks worldwide.
• • Libraries: Many library systems use Codabar for patron cards and book labels. The start/stop characters help identify the type of item (patron card vs book vs media).
• • FedEx airbills: FedEx tracking numbers on older airbill formats use Codabar barcodes, although newer labels have migrated to Code 128.
• • Photo labs: Film processing envelopes and order tracking in photo labs traditionally used Codabar due to its simplicity and the colon and slash characters needed for date/time encoding.
• • Japanese logistics: In Japan, Codabar (known as NW-7) is specified in JIS X 0503 and used in some logistics and warehousing applications.

How to Create a Codabar Barcode

1. 1. Open the Barcode Generator and select Codabar.
2. 2. Enter your data using digits 0–9 and the special characters - $ : / . + as needed. Select your start and stop characters (A, B, C or D).
3. 3. Adjust bar width, height and the wide-to-narrow ratio to match your printing and scanning requirements.
4. 4. Download and test-scan the barcode with your equipment before deployment.

All processing happens locally in your browser – no data upload, no registration, unlimited generation.

Codabar vs Modern Alternatives

Codabar was designed in an era when printing technology was less precise and scanners were less capable. Today, Code 128 and Code 39 offer superior density, larger character sets and stronger error detection. For new applications, these modern symbologies are almost always the better choice.

However, Codabar remains relevant where existing infrastructure – scanners, software systems, databases and workflows – is built around it. The cost of migrating an entire blood bank or library system to a new barcode format can be substantial, so Codabar continues to coexist alongside newer standards.

If you are building a new system and considering Codabar, evaluate whether Code 128 (for full ASCII support and high density) or Code 39 (for government/military compatibility) might be a better long-term investment.

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