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Codabar is an old numeric barcode that’s easy to print, even on simple printers. Its letter start and stop characters make it easy to recognize, and in some systems they carry meaning of their own.

Decode one

Scan or paste a barcode and see every part of it.

Make one

Generate a valid barcode from fields.

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Where you’ll see it

  • Library books and library cards.
  • Older healthcare labels. Blood banks used Codabar before moving to ISBT 128.
  • Older shipping and photo-processing paperwork.
It also goes by other names: NW-7, mainly in Japan, and Code 2 of 7.

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Anatomy

Each character is seven elements, four bars and three spaces, and a narrow gap separates one character from the next.

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Start and stop letters

Any of the four letters can start or stop a barcode, and they don’t have to match. Some systems use the combination to mean something, such as which kind of item the label is on. Other systems ignore them. Some vendors write the letters as T, N, * and E instead of A to D.

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Check digit

Codabar doesn’t require a check digit. Some applications add one, and the method depends on the application. Nothing in the barcode says whether one is there.
  • Code 39: a similar-era barcode with letters as well as digits.
  • Code 128: the usual choice for new labels.

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Gotchas

  • Letters at both ends. Depending on the scanner’s settings, the start and stop characters are either included in the scan or dropped. Decide which you expect and set the scanner to match.
  • Different letters for the same barcode. Scanners that use T N * E report different start and stop characters for the same label.

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Scanning it in your app

Fix the length if you can: Codabar has no required check digit to catch a bad read. See Validation.

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Specification

  • AIM USS Codabar: the Codabar barcode specification.