What are the A, B, C and D characters for?

They are start and stop delimiters. Different industries assign them meanings, so match whatever your existing system uses — commonly A at the start and B at the end.

Which characters can Codabar encode?

Digits 0-9 plus the symbols - $ : / . and +, framed by a start and stop letter from A to D.

Is Codabar still used today?

Yes, heavily in libraries and blood banks where the installed base of scanners and software would be expensive to replace.

Does Codabar have a check digit?

It is self-checking at character level and a modulo-16 check digit is optional. Include one in your value if your system requires it.

Why do libraries still use Codabar?

Millions of existing spine labels use it, it is self-checking, and it decodes reliably on decades-old readers. Replacing it would mean relabelling entire collections.

What do the A, B, C and D characters mean?

They are start and stop delimiters. Some systems assign meaning to the pair used; most simply need them to be consistent.

Is Codabar the same as Code 2 of 7?

Yes. Codabar, Code 2 of 7, NW-7 and Monarch all refer to the same symbology.

Can Codabar encode letters?

Only as start and stop characters. The data payload is numeric plus a small set of punctuation.

Is Codabar a good choice for a new system?

Generally no. Choose Code 128 unless you are matching an existing Codabar deployment.

Barcode generator / Codabar

Codabar Generator

Create Codabar barcodes free online for libraries, blood banks and logistics. Encode digits and symbols, download as PNG or SVG. No watermark.

Barcode data

Start and stop letter A-D around digits and - $ : / . + characters.

Bar height80px

Show number under barcode

PNG resolution Pro

Preview

No watermark, no signup, unlimited PNG downloads. Rendered in your browser — the value you type never leaves your device. Vector SVG and high-resolution PNG are included with Pro.

What is Codabar used for?

Codabar is a self-checking numeric symbology wrapped in a start and stop letter from A to D. It was designed to be printable on early dot-matrix and impact printers, which is why it took hold in libraries, blood banks, photo labs, and courier networks — and why so many of those systems still run on it decades later.

Each Codabar value carries its own structure, so it stays readable even on poor-quality print stock. Use it when an existing library management system, blood-product register, or shipping platform explicitly expects Codabar; for new projects Code 128 is the better default.

Library circulation systems
Blood banks and pathology labs
Courier and photo lab tracking

Codabar specification

Character set	0-9 and - $ : / . +
Start/stop	Letters A, B, C or D at each end
Length	Variable
Check digit	Optional, application defined
Self-checking	Yes — high read reliability without a check digit
Quiet zone	10 modules either side
Best for	Libraries, blood banks, photo labs and legacy logistics

How to generate a Codabar barcode

1
Enter your numeric value, including any hyphens or colons your system uses.
2
Choose start and stop characters that match your existing labels — libraries commonly use A and B.
3
Set a bar height suited to handheld scanning across a shelf or bench.
4
Download SVG for label sheets, PNG for one-off replacements.
5
Scan the printed label with the same reader used at your circulation or intake desk.

Troubleshooting scan failures

Existing labels have letters at each end

Those are the start and stop characters. Match them exactly so your database lookups line up with historic records.

Unsupported characters rejected

Codabar takes digits plus - $ : / . + only. Anything else needs Code 39 or Code 128.

Duplicate item numbers

Codabar carries no built-in uniqueness. Sequence numbers in your catalogue system, not by hand.

Old labels scan but new ones do not

Compare module width. Reprints often come out smaller when a label template is scaled to fit.

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