How to gtin & barcode validator without breaking your data

A barcode column that lost its leading zeros still looks like a number. It passes a spreadsheet review and fails at the marketplace, three days after upload.

You see this most often in product feeds, barcode imports, inventory reconciliations. Excel treats 0012345678905 as a decimal and stores 12345678905 — the zeros vanish before you ever see them.

Doing it in four steps

1. Paste one barcode per line
2. Run the validator
3. Read the padded suggestion
4. Fix the source column as text

The whole thing runs locally in the browser tab: no upload, no account, no queue. When the page says "removed 37 lines", that number comes from the file you just pasted, not from a sample.

The suggested padded value is what usually should have been in the column, which is more useful than a bare "invalid".

For the full picture — imports, feeds, variants, identifiers — see the pillar guide: Shopify product data management.

Try it on your own file

Open GTIN & Barcode Validator and paste a sample. It is free, it does not store anything, and you do not need an account. If the file is sensitive, save the page locally and run it offline.

Questions people ask

Which lengths are valid?

GTIN-8, 12, 13 and 14. Anything else is flagged with the padded value you probably meant.

Does it check the check digit?

Yes, the GS1 check digit is recomputed for every value.