EAN/UPC Check Digit Calculator
Calculate or validate UPC-A, EAN-8 and EAN-13 check digits locally in your browser.
Calculate or validate barcode check digits
Choose the barcode format and enter the numeric data digits or a complete barcode.
How the calculation works
UPC-A, EAN-8 and EAN-13 use a modulo-10 check digit. Starting from the rightmost data digit, the algorithm applies alternating weights of 3 and 1, sums the weighted digits, and chooses the final digit that makes the total a multiple of 10.
How to use the result
Use calculation mode before creating a barcode from an assigned company/product number, or paste a full code to catch typing errors. A valid check digit verifies arithmetic consistency only; it does not prove that a number has been legitimately assigned.
Assumptions and limitations
The tool does not query GS1 or any product registry. It cannot verify ownership, allocation, product identity or barcode print quality. Leading zeros are preserved because the input is handled as text.
Example
The format selector avoids the ambiguity of a 12-digit value, which could otherwise be interpreted as a complete UPC-A or as the data portion of an EAN-13.