What is Codabar?
Codabar (also known as NW-7 or USD-4) is a self-checking linear barcode that encodes digits and the symbols - $ : / . +, wrapped in start and stop letters A-D. It dates back to 1972 and is still the standard symbology in US blood banks, library circulation systems, photo finishing, air waybills and hotel luggage tags, because it prints reliably at low resolution and older fixed scanners read it without configuration.
Common Uses for Codabar
- Blood bag and donor ID labels in blood banks
- Library book checkout and circulation labels
- Air waybills and logistics tracking tags
- Photo lab envelopes and membership cards
Codabar start and stop characters
Every Codabar symbol must begin and end with one of the letters A, B, C or D. The pair you choose carries no data - it simply tells the scanner where the code starts and stops and in which direction to read. Enter the letters yourself, for example A40156B or C9876543D, and the tool encodes them as part of the symbol. If your target system specifies a particular pair, match it; otherwise any consistent pair works.
Codabar vs Code 39
Both are older, self-checking symbologies readable by almost any scanner, but they encode different data: Codabar is digits-plus-a-few-symbols, while Code 39 adds uppercase letters. If your data contains letters, use Code 39 or Code 128. Choose Codabar when the system you feed - a library system, blood bank software or airbill printer - explicitly expects NW-7/Codabar labels.
Codabar printing tips
Codabar is forgiving of print quality, but keep the narrow bar at least 0.25mm and leave a quiet zone of about 10 times the narrow bar on each side. Because it is a low-density code, longer numbers get wide quickly - keep values to 12-16 characters for shelf-edge or wristband labels, and print a test scan before running the full batch.
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