GTIN check digit calculator
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The last digit of a GTIN is calculated from the digits before it. Type a full number to check it, or leave off the last digit of a GTIN-8 or GTIN-12 to work it out.
- Check digit
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- Format
- Prefix
A correct check digit shows that the number is well formed, not that anyone owns it or that it was assigned to this product. The bars are a preview, not artwork for printing. Your number stays in your browser.
How the calculation works
- Start from the digit next to the check digit and move left. Multiply the digits by 3, 1, 3, 1 and so on.
- Add the results together.
- Subtract the sum from the nearest equal or higher multiple of ten. The result is the check digit.
The same method applies to GTIN-8, GTIN-12, GTIN-13 and GTIN-14, as well as to other GS1 keys such as the SSCC.
Worked example
This is the GTIN-13 example GS1 uses, 629104150021 without its check digit.
| Digit | 6 | 2 | 9 | 1 | 0 | 4 | 1 | 5 | 0 | 0 | 2 | 1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Multiply by | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 | 1 | 3 |
| Result | 6 | 6 | 9 | 3 | 0 | 12 | 1 | 15 | 0 | 0 | 2 | 3 |
The results add up to 57. The nearest equal or higher multiple of ten is 60, and 60 − 57 = 3. The full number is 6291041500213.
What a correct check digit proves
Only that the digits are consistent with each other. It does not show that the number was assigned, who it belongs to or which product it identifies. For that, GS1 offers a lookup called Verified by GS1.