Is this EAN/UPC number correct? (check digit)
EAN / UPC / GTIN validator online - verify a barcode's check digit, or compute it from a numeric prefix.
Works for every common format: EAN-8 (8 digits), UPC-A (12), EAN-13 (13), GTIN-14 / ITF-14 (14).
Useful when a number arrives from an invoice, return list, or supplier sheet and you need to confirm nobody mistyped a digit.
Everything is computed locally in your browser - no data is sent.
How to use it
- Pick a mode: "Validate" (you have the full number and want to verify the last digit) or "Compute" (you have the payload without the check digit and want to calculate it).
- Type or paste the code. Spaces, dashes, other characters are stripped automatically.
- The format (EAN-8, UPC-A, EAN-13, GTIN-14) is detected from the digit count.
- The result: status "check digit OK" or "invalid", or the complete number with check digit appended ready to feed into a barcode generator.
When this is useful
Where a GTIN validator saves time - typical scenarios:
- Manufacturers and importers - before sending a GTIN to the label printer, confirm the check digit.
- Online stores - validate EAN numbers before importing into your catalog. Wrong check digit = no match on Amazon, eBay, or other marketplaces.
- Warehouses and logistics - ITF-14 (GTIN-14) on case packs.
- Pharma - GTIN on medications before serialization.
- Invoices and return slips - quickly confirm a partner copied the number correctly.
After validating, jump to the barcode generator to render it, or to the barcode reader to scan it from an image.
Questions and answers
It's the last digit of the number, computed mathematically from the rest. A simple error-detecting code: if any single digit is mistyped, the check digit almost certainly stops matching. GS1's mod-10 standard: sum the digits with alternating weights 3 and 1, check digit = (10 - (sum mod 10)) mod 10.