Interleaved 2 of 5 Barcode Generator for Even Digit Strings

Reading the name Interleaved 2 of 5

Interleaved 2 of 5 descends from the uniform symbology specification family of numeric codes, and its name is a literal description of the layout. Each digit is five elements, two of them printed wide. In a plain 2 of 5 code those digits sit side by side with a gap between them; ITF reclaims that wasted gap by interleaving, so the bars of the symbol spell the first digit of a pair and the spaces spell the second.

Two digits therefore share one block of ten elements, and that is exactly why the digit count has to be even. There is no such thing as half a pair in an interleaved symbol, so this page rejects a value of seven or eleven digits instead of quietly padding it. Prefixing a zero is the normal fix, and most ITF installations standardise on a fixed, even field length precisely so the question never comes up.

Density is the reason people stay with it. Because the gaps are doing work rather than separating characters, an interleaved pair costs about ten modules, so a ten-digit batch number that would sprawl in a character-per-block format fits on a small ticket. The cost of that economy is strictness: the reader has to stay aligned with the pair boundaries from the first element to the last, which is why a smudged or chopped end shows up as a complete failure to read rather than as one wrong digit.

How the validator treats your input

Nothing here is silently corrected. Padding, stripping or substituting a character would change the number your warehouse system is looking for, so the preview reports the problem and leaves the decision to you.

ITF and ITF-14 are different jobs

The most common mix-up is between plain ITF and ITF-14. ITF-14 uses this same interleaved encoding but carries a fourteen-digit GTIN, in which the last digit is a modulo-10 check calculated over the thirteen before it, and it is printed inside bearer bars at a defined X-dimension on corrugated cases. When a customer asks for a barcode on the outside of a shipping carton they nearly always mean ITF-14, not the bare symbology you are building here.

Neither ITF page in this studio draws bearer bars, so the frame comes from the carton artwork on top of the file you download here. What plain ITF is genuinely good for is everything your own system numbers: batch codes, bin and location tags, pallet identifiers returned to you by a captive fleet of readers.

Length, printing and the scanner settings

With no checksum in the symbology, a misprint or a partial read can turn into a different number rather than a failed scan. Sites handle that by constraining the reader instead of the label: a scanner set to accept only ten-digit ITF refuses everything else, and that refusal is the protection. So keep every ITF value in one system to the same digit count, and write that count into the reader configuration.

Fixed field length also settles the leading-zero question before it becomes an argument. If the numbering scheme says ten digits, a value that comes out of your software as 1234567 has to be padded to 001234567, and it has to be padded in the database rather than on the label - otherwise the printed symbol and the stored record disagree, and the mismatch surfaces at the worst possible moment during a stock count.

• Choose the X-dimension - the narrowest element - first; wide elements run roughly two to three times it and the reader must expect the same ratio range.
• Give both ends of the symbol clear space; the margin control supplies background, but the reader specification sets how much is enough.
• Interleaved 2 of 5 is often switched off in newer reader firmware, so a code that "will not scan" is usually a settings problem before a print problem.
• Print one label, scan it, and check the full returned string against what you typed before committing a run.