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Codabar Barcode Generator for Libraries and Labs

Create Codabar barcodes, the simple numeric format still used on library cards, lab samples, blood bags and air waybills.

  • 100% free
  • No sign-up
  • Never expires
  • No watermark
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How to use the Codabar generator

  1. 1

    Wrap your value

    Start and end the value with one of the letters A, B, C or D, for example A12345678B. Your system documentation will say which pair to use.

  2. 2

    Check the preview

    The preview updates as you type and shows an error for unsupported characters.

  3. 3

    Download

    Export the barcode as SVG or PDF for card printing, or PNG for labels.

Features

  • Digits plus - $ : / . + characters
  • Start and stop characters A, B, C or D
  • Self-checking structure that tolerates dot-matrix and inkjet printing
  • Export SVG, PNG or PDF
  • Generated in your browser with no account or watermark

A format built for simple printers

Codabar dates from 1972 and was designed to be printed by the impact and dot-matrix printers of the time. Each character is separate from its neighbours, and every character has a fixed structure, which makes the format forgiving of uneven ink and slight smudging.

It became the standard for many library systems, blood banks (it was used in the ISBT system before ISBT 128), photo labs and courier air waybills. Many of those installations still run today, which is why new Codabar labels are still printed.

Codabar symbol with the start and stop characters outlined at both ends and the data characters between them
The A-D pairs at each end tell the reader where the record starts and which direction to read it.

Codabar character set

TypeCharacters
Data0 1 2 3 4 5 6 7 8 9 - $ : / . +
Start / stopA B C D (sometimes shown as T N * E)

When to choose something else

  • For new systems with no Codabar requirement, use Code 128. It is denser and has a built-in checksum.
  • For blood and tissue products, modern systems use ISBT 128, which is based on Code 128.
  • If you are replacing an existing card or label, match the start and stop characters used on the old ones.

How a Codabar character is built

Every Codabar character is seven elements wide: four bars and three spaces, with exactly two of the seven printed wide. The characters sit side by side with a narrow gap between them, and nothing is shared between neighbours. That per-character structure is why the format survives impact and dot-matrix printing - smudged ink ruins one character rather than shifting the alignment of the whole symbol.

The wide-to-narrow ratio is a reader setting, usually 2:1 or 3:1. If the symbol is generated for one ratio and the scanner is configured for another, it fails in a way that looks like a print defect, so fix the ratio in both places before the first run.

PropertyValue
Elements per character4 bars + 3 spaces, two of them wide
Data characters0-9 plus - $ : / . +
Start and stopA, B, C or D, one at each end
Check digitNot part of the format
LengthVariable; each character adds its own fixed block

Frequently Asked Questions

Which start and stop letters should I use?

Use whatever your library or lab system expects. Many library systems use A and B; others accept any pair. Check an existing card with a scanner to see the full value.

Does Codabar have a check digit?

The format is self-checking, so no check digit is required. Some applications add one, such as the modulo-16 check digit, as part of the data.

Is Codabar the same as NW-7?

Yes. NW-7 is the name used in Japan. Other names include USD-4, Code 2 of 7 and ABC Codabar.

Why does the scanner return the letters as well as the number?

Most readers can be set to transmit or strip the start and stop characters. If your system expects digits only, change that setting rather than editing the data, or the next reader you deploy will behave differently again.

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