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EAN / UPC Validator
Paste one barcode per line to bulk-check EAN-13 and UPC-A check digits before you upload a listing or print labels.
| Input | Type | Check digit | Result |
|---|
Why check digits matter before you list
Every EAN-13 and UPC-A code ends in a check digit calculated from the other 12 digits using a GS1 weighted-sum formula (alternating weights of 1 and 3). Marketplaces validate this before accepting a barcode against a listing - a code that fails the check almost never gets rejected with a clear reason, it just silently blocks the listing or throws a generic "invalid barcode" error. Running your codes through this first, especially before a bulk upload of dozens or hundreds of SKUs, catches the typo before it costs you a support ticket.
How this works
- EAN-13 and UPC-A both use a GS1 weighted-sum check digit (weights 1 and 3, alternating).
- A failing check digit usually means a typo, or a code copied with a missing/extra digit.
- UPC-A is treated as EAN-13 with a leading zero for the calculation.
Frequently asked questions
Why does a marketplace reject my listing over the barcode?
Amazon, Flipkart and Meesho all validate the GTIN (the EAN/UPC number) against its check digit before accepting a listing. If the last digit does not match what the first 12 digits compute to, the barcode is either mistyped, missing a digit, or was copied from an image at the wrong resolution - the listing gets rejected or the field errors out.
My barcode is failing - what should I check first?
Almost always it is a copy-paste issue: an extra space, a missing leading zero (common with UPC-A codes that some spreadsheet tools strip), or one transposed digit. Re-copy the code directly from the product packaging or your GS1 certificate rather than retyping it by hand.
Does this tool generate new barcodes, or only check existing ones?
This tool only validates codes you already have. To generate new, correctly-structured EAN-13/UPC-A codes with the check digit calculated automatically, use the Barcode Generator tool.
I do not have a GTIN for my product - can I make one up?
No. EAN/UPC numbers are allocated by GS1 (or resold in bulk by GS1-licensed distributors) and are meant to be globally unique. Using a code you invented, or reusing someone else's brand's real barcode, risks listing suppression or an IP complaint once the marketplace or the brand owner notices the mismatch.
Does this work for FNSKU labels?
No - FNSKU is Amazon's own internal barcode format for FBA inventory tracking, not a GS1 EAN/UPC. This tool only validates standard EAN-13 and UPC-A retail barcodes.
Is my data uploaded anywhere?
No. The check digit calculation runs entirely in your browser using plain JavaScript - nothing you paste here is sent to Servicxy or anyone else.
Need to generate fresh, correctly-structured codes instead? Try the Barcode Generator.