GTIN / UPC / EAN Check Digit Calculator
Calculate the check digit for a new barcode, or validate an existing one. Works with GTIN-8, UPC-A (GTIN-12), EAN-13 and GTIN-14. Free, instant, no sign-up.
How it works
The last digit of every GTIN (Global Trade Item Number) is a check digit computed from all the other digits with the GS1 Mod-10 algorithm. Scanners and retail systems use it to catch typing and reading errors.
- Starting from the rightmost data digit, multiply digits alternately by 3 and 1.
- Add up all the results.
- The check digit is the smallest number that brings the sum up to the next multiple of 10.
GTIN formats at a glance
| Format | Total length | Typical use |
|---|---|---|
| GTIN-8 (EAN-8) | 8 digits | Small packages |
| GTIN-12 (UPC-A) | 12 digits | Retail products, North America |
| GTIN-13 (EAN-13) | 13 digits | Retail products, worldwide |
| GTIN-14 | 14 digits | Cases / shipping units |
FAQ
What is the difference between UPC, EAN and GTIN?
GTIN is the umbrella term. A UPC-A barcode is a 12-digit GTIN mostly used in North America; an EAN-13 is a 13-digit GTIN used worldwide. A UPC-A becomes a valid EAN-13 by adding a leading zero.
Why is my barcode rejected by Amazon or Google?
Most rejections happen because the check digit is wrong (typo) or the GTIN was not issued by GS1. First validate the code with the tool above; if the check digit is correct but the code is still rejected, verify the GS1 prefix ownership.
Can I invent my own GTIN?
No. Valid GTINs are issued through GS1. This calculator helps you compute or verify check digits for codes you legitimately manage.
Validating thousands of barcodes?
Use the free bulk barcode validator — or our pay-per-use API, with 25 free calls per month.
Results are computed with the official GS1 Mod-10 formula and provided as-is, without warranty. This tool does not verify GS1 prefix ownership.