What is Check Digit Algorithm?

The check digit is the last digit of any UPC or EAN barcode. It's mathematically derived from the other digits to detect scanning errors.

How do I look up a check digit algorithm barcode?

Enter any barcode at upc.dev or call GET /v1/product/{barcode}. upc.dev aggregates dozens of authoritative sources and returns name, brand, category, recalls, and full intelligence.

Is Check Digit Algorithm the same worldwide?

Check Digit Algorithm is part of the GS1 global identification system. Check digits, prefix ranges, and format rules are standardized globally.

Where can I see a real Check Digit Algorithm example?

Live example from the canonical catalog: 000000000307. View full intelligence at https://upc.dev/product/000000000307

Check Digit Algorithm — Barcode Guide

What is a Check Digit?

A check digit is a form of redundancy check used to detect errors in identification numbers. It is the final digit in any UPC-A, EAN-13, or GTIN code, calculated from all preceding digits. If a scanner misreads one digit, the check digit calculation fails — and the scanner knows to try again.

UPC-A / EAN-13 Algorithm (Luhn-like)

Example: Calculate check digit for 036000291452 (12 digits)

Step 1: Take the first 11 digits: 0 3 6 0 0 0 2 9 1 4 5
Step 2: Multiply odd positions (1,3,5,7,9,11) by 1: 0,6,0,2,1,5 → sum=14
Step 3: Multiply even positions (2,4,6,8,10) by 3: 3,0,0,9,4 → sum=48
Step 4: Total = 14 + 48 = 62
Step 5: Check digit = (10 - (62 % 10)) % 10 = (10 - 2) % 10 = 8

Full UPC: 036000291452 ✓

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