GTIN Check Digit Calculator
Calculate and validate check digits for GTIN codes, UPC, EAN, and other barcodes using mod 10 algorithm
Calculate GTIN Check Digit
Supports GTIN-8, GTIN-12 (UPC), GTIN-13 (EAN), GTIN-14, GSIN, and SSCC codes
Example Calculation
GTIN-13 (EAN-13) Example
Code without check digit: 123456789012
Step 1: Multiply odd positions (from right) by 3: 1×3 + 3×3 + 5×3 + 7×3 + 9×3 + 1×3 = 78
Step 2: Multiply even positions by 1: 2×1 + 4×1 + 6×1 + 8×1 + 0×1 + 2×1 = 22
Step 3: Sum: 78 + 22 = 100
Step 4: Check digit: (10 - (100 mod 10)) mod 10 = 0
Complete code: 1234567890120
GTIN Code Types
GTIN-8 (EAN-8)
8-digit code for small packages
Used when space is limited
GTIN-12 (UPC)
12-digit Universal Product Code
Common in North America
GTIN-13 (EAN-13)
13-digit European Article Number
Most common globally
GTIN-14 (ITF-14)
14-digit for trade items
Used for wholesale/logistics
Check Digit Tips
Check digits help detect typing errors in barcodes
Uses mod 10 algorithm with alternating weights
Weights are 3 and 1, starting from the right
If calculated check digit is 10, use 0 instead
Understanding GTIN Check Digits
What is a Check Digit?
A check digit is a form of redundancy check used for error detection in identification numbers. It's calculated from other digits in the code using a specific algorithm and helps detect common data entry errors like single digit mistakes or transposition of adjacent digits.
Why are Check Digits Important?
- •Detect typing errors when entering barcodes manually
- •Ensure data integrity in retail and inventory systems
- •Validate barcode scans are accurate
- •Prevent processing of invalid product codes
Mod 10 Algorithm
- Starting from the right, multiply every odd position by 3
- Multiply every even position by 1
- Sum all the products
- Subtract the sum from the next highest multiple of 10
- If the result is 10, use 0 as the check digit
GTIN Standards
GTIN (Global Trade Item Number) is a family of data structures developed by GS1 for the unique identification of trade items worldwide.
- GTIN-8: Short codes for small packages
- GTIN-12: UPC codes used in North America
- GTIN-13: EAN codes used globally
- GTIN-14: Used for trade items and logistics