GTIN check digit calculator
Enter a GS1 number with or without its final digit. The calculator applies the GS1 modulo-10 algorithm, returns the correct check digit and tells you whether an existing one is valid.
7, 11, 12, 13 or 17 digits → the check digit is calculated. 8, 12, 13, 14 or 18 digits → the existing check digit is verified.
- Format
- GTIN-13 / EAN-13
- Check digit
- 1
- Complete number
- 4001234567891
How the mod-10 check digit works
- Write the digits right to left, starting after the check-digit position.
- Multiply alternating by 3 and 1, starting with 3 at the rightmost position.
- Add all products together.
- Subtract the sum from the next multiple of ten – that difference is the check digit.
Frequently asked questions
- Which numbers does this cover?
- Every GS1 identifier that uses the standard mod-10 scheme: GTIN-8, GTIN-12 (UPC-A), GTIN-13 (EAN-13), GTIN-14 (ITF-14) and SSCC-18.
- Is my number sent anywhere?
- No. The calculation runs in JavaScript inside your browser; nothing is transmitted or stored.
- Why does my number fail the check?
- Usually a typo, a missing leading zero, or a number that was truncated when exported from Excel as a numeric cell.