1. What is GTIN-14?

GTIN-14 (Global Trade Item Number) is a 14-digit identifier used for trade items at various packaging levels. It's part of the GS1 system for product identification and includes a check digit for validation.

2. How Check Digit Calculation Works

The calculator uses the standard GTIN check digit formula:

Where:

• Start with the first 13 digits (position 1-13)
• Sum all digits, multiplying digits in odd positions by 3
• Calculate the check digit that makes the total sum a multiple of 10

Example Calculation: For digits 1234567890123:

1. Multiply odd positions by 3: (1×3) + 2 + (3×3) + 4 + (5×3) + 6 + (7×3) + 8 + (9×3) + 0 + (1×3) + 2 + (3×3)
2. Sum all values: 3 + 2 + 9 + 4 + 15 + 6 + 21 + 8 + 27 + 0 + 3 + 2 + 9 = 109
3. Calculate check digit: (10 - (109 % 10)) % 10 = (10 - 9) % 10 = 1
4. Complete GTIN-14: 12345678901231

3. Importance of Check Digits

Details: Check digits help detect errors in GTIN entry or transmission. They catch about 90% of common errors like single-digit mistakes or transpositions.

4. Using the Calculator

Tips: Enter the first 13 digits of your GTIN-14 (without the check digit). The calculator will compute the correct check digit and display the complete GTIN-14.

5. Frequently Asked Questions (FAQ)

Q1: Is this the same calculation used for other GTIN formats?
A: Yes, the same check digit calculation is used for GTIN-8, GTIN-12 (UPC), GTIN-13 (EAN), and GTIN-14.

Q2: What if my number already has a check digit?
A: You can enter the first 13 digits to verify the check digit matches the 14th digit.

Q3: Why does the calculation use modulo 10 twice?
A: The second modulo 10 ensures the result is a single digit (0-9) even when the sum is a multiple of 10.

Q4: Can this detect all errors in GTIN entry?
A: No, it catches most but not all errors. Some transpositions (like 09→90) won't be detected.

Q5: Where is GTIN-14 used?
A: GTIN-14 is typically used for cases, pallets, or other trade items containing multiple consumer units.