BACKLANE / TOOLS FOR SELLERS
EAN / GTIN checker
Clean product identifiers. Less detective work.
Check one identifier or an entire product list for structural errors. Get a clear report before looking more closely at your listings.
No sign-up · Calculated in your browser
01 / INPUT
Your inputs
One identifier per line. GTIN-8, UPC/GTIN-12, GTIN-13 and GTIN-14. Keep leading zeros.
CSV or text, up to 2 MB, 2,000 data rows, 100 columns and 10,000 characters per field. The file stays on your device.
Fictional example loaded. Replace these figures with your own inputs.
02 / OUTPUT
Your result
Enter your figures and calculate the result.
- Checked
- —
- Correct check digit
- —
- Invalid
- —
- Repeated entries
- —
Checks cover format, length, check digit and identical entries in your list. A correct check digit does not verify GS1 assignment, product identity or marketplace approval.
Preview of the first 50 rows. The CSV report includes all checked rows.
| Row | EAN / GTIN | Check | Repeated entry |
|---|
The CSV report preserves leading zeros as characters. Import the GTIN column into Excel as text to stop Excel removing them.
This tool processes your inputs locally in your browser. It does not upload your figures or files, or save them permanently.
03 / METHOD
How the calculation works
GTIN check digit = amount needed to round the weighted digit sum up to a multiple of ten
Starting from the rightmost digit before the check digit, multiply alternate digits by 3 and 1. The amount needed to bring the sum up to a multiple of 10 is the check digit. Supported lengths are GTIN-8, UPC/GTIN-12, GTIN-13 and GTIN-14. Repeated entries are detected using identical identifiers, ignoring surrounding whitespace.
An example to work through
Fictional structural examples: the twelve-digit payload 400638133393 produces check digit 1. The identifier 4006381333931 passes this structural check; 4006381333932 does not. This does not verify assignment or identify a product.
This checker does not query a product database. Correct structure does not confirm official GS1 assignment, brand or product identity. Different GTIN lengths are not automatically merged into a single identifier.
Verified by GS1CONTINUE WITH YOUR OWN MARKETPLACE DATA
What errors do your marketplaces report?
Move from checking identifiers to reviewing your product data: read available listing statuses, required attributes and import reports in your AI chat.
BACKLANE / STARTER PROMPT
Check the available product data and listing statuses for my selected products across my connected marketplaces. Use confirmed EAN or SKU mappings. Show reported errors, missing required attributes and available import reports by channel. Flag data gaps. Do not change product data.
Frequently asked questions
Does the checker confirm that my EAN is officially assigned?
No. It checks structure. Use Verified by GS1 to check assignment and registered company or product information. A correct check digit does not guarantee marketplace approval.
Can I check a CSV with multiple columns?
Yes. After choosing the file, select the product identifier column and check the header-row setting. Supported files are UTF-8 CSVs with comma, semicolon or tab separators, up to 2 MB and 2,000 data rows.