CheckDigit
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GS1 Mod-10 utility

GS1 check digit calculator for GTIN, EAN and UPC

Enter the digits before the check digit, choose the identifier format, and calculate the exact final digit locally with every weighted step visible.

Exact GS1 Mod-10 rule

How to calculate a check digit

  1. Starting with the rightmost body digit, multiply the digits alternately by 3 and 1.
  2. Add the weighted products and find the remainder after division by 10.
  3. Subtract the remainder from 10 and take the result modulo 10. This is the check digit.

The same rule applies to GTIN-8, UPC-A / GTIN-12, EAN-13 / GTIN-13, GTIN-14, GLN-13 and SSCC-18; only the required length changes.

Worked GTIN-13 / EAN-13 exampleBody: 629104150021

Weighted sum = 57; (10 − 57 mod 10) mod 10 = 3.

Check digit: 3 · Complete value: 6291041500213

Calculator

GS1 Mod-10 check digit

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Choose an action

Enter exactly 12 ASCII digits.

A matching check digit detects some entry errors. It does not prove that an identifier was issued, assigned correctly, authentic, or linked to a particular product or location.

Supported formats

Exact lengths, one shared rule

GTIN, GLN and SSCC use the same GS1 Mod-10 arithmetic but have different required lengths. CheckDigit validates the length before calculating.