ITF-14 barcode generator
The barcode printed straight onto corrugated cardboard. Fourteen digits identifying a carton rather than the items inside it, in a symbology built to survive a printing surface that cannot hold fine detail.
Interleaved 2 of 5, and why the count must be even
The interleaving is the whole idea. One digit is encoded in five bars, the next in the five spaces between them, and the two are drawn at the same time. That packs two digits into the width one would normally take, which is how ITF stays compact enough for a carton.
It also means digits only come in pairs. An odd count cannot be interleaved, so this encoder refuses one rather than padding a zero on silently. Which end a pad goes on changes the number, and quietly changing a carton code is worse than an error message.
Fourteen digits, and what they are
An ITF-14 carries a GTIN-14: an indicator digit saying what packaging level this is, the GTIN of the product inside, and a check digit. So a case of twelve and a case of twenty-four of the same product differ in the first digit, and both relate visibly to the EAN-13 on the individual item.
Give this page thirteen digits and the check digit is computed. The symbol comes out at 135 modules, measured, which is wider than a retail EAN-13 because there are more digits to carry.
Bearer bars and the reason they exist
An ITF-14 on a carton is conventionally printed inside a heavy frame called a bearer bar. It is not decoration. Printing onto corrugated board spreads ink, and a partially printed bar at the edge of the symbol can be read as a narrower bar, which shifts every digit after it.
The frame guarantees the outer elements are fully formed and gives the scanner a clean boundary. If you are producing artwork for a real carton, the frame and the specified quiet zones are part of the job, and the SVG download is the format to take into that artwork.
ITF-14, ITF and GS1-128
- ITF-14 for the carton GTIN, printed directly on board. Fourteen digits, nothing else, and it is what a distributor expects to see.
- Plain ITF when you need an even-length numeric string that is not a GTIN. Same interleaving, no fixed length, no check digit convention.
- GS1-128 when the label has to carry more than the GTIN: batch, expiration, serial, count. ITF-14 has room for one number and no way to say what any other field means.
Questions
Why was my ITF rejected for having an odd number of digits?
Because interleaving encodes digits in pairs, one in the bars and one in the spaces, so an odd count has nothing to pair with. Padding with a zero would change the number, and doing that silently is worse than refusing, so the encoder refuses.
Do I need the bearer bar frame?
For a real carton, yes, and the specified quiet zones with it. The frame protects the outer bars from ink spread on corrugated board. For a screen fixture or a test image it changes nothing about the encoded data.
Is an ITF-14 the same number as the EAN-13 on the item?
Related, not the same. A GTIN-14 wraps the item's GTIN with an indicator digit for the packaging level and recomputes the check digit. The case and the bottle are deliberately different numbers.
Can ITF hold letters?
No. Interleaved 2 of 5 is numeric only, and that is not a limitation of this tool. If the carton code contains letters, it is not an ITF-14, and Code 128 or GS1-128 is where it belongs.
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