GTIN Check Digit Calculator
Compute the GS1 modulo-10 check digit for any GTIN, EAN, or UPC. Enter the number without its last digit and get the complete, valid barcode number.
Generate the barcode, then protect it
Draw the barcode from your complete GTIN with our Barcode Generator — then add FirstScanIt's signed QR layer so the product can prove it's genuine, not just identify itself.
Learn MoreHow the GTIN Check Digit Works
Every GTIN, EAN, and UPC ends in a single check digit that lets a scanner detect mis-reads and typos. It is calculated from the other digits using the GS1 modulo-10 algorithm: working from the right, each digit is multiplied alternately by 3 and 1, the products are summed, and the check digit is whatever brings that sum up to the next multiple of 10.
Worked Example
For the 12 data digits 890123456789: multiply alternately by 3 and 1 from the right, add the results, then subtract that sum from the next multiple of 10. The remainder (mod 10) is the check digit, giving a complete EAN-13.
Generate vs. Validate
This calculator adds the correct final digit to a number you're creating. To check an existing barcode — and decode its country prefix and company prefix — use the GS1 Barcode Validator. A mismatched check digit can indicate a typo, a printing fault, or a counterfeit label.
Note: A valid check digit confirms the number is well-formed, not that the GTIN is registered to a company. Official GTINs are allocated by GS1. Runs entirely in your browser.