This is a pretty easy process. Once you’ve received your company prefix from GS1, you just need to come up with a convention for your product number. Depending if purchased a 6 or 9 digit company prefix will dictate how you do this. Given that there are less digits in the 9-digit company prefix for your product ID’s (supports up to 100) I’m going to use that for examples. Many of the same concepts can be applied to the 6-digit prefix.

**Tip:** To calculate your check digit, enter your 11 digit UPC you create here on the GS1 check digit calculator. The last digit of a bar code number is a computer check digit which makes sure the bar code is correctly composed. You cannot make this number up and must use the above calculator with 11 digits to get your full 12 digit UPC.

### Example #1

Just start from 00 and increment 1 by 1.

- 0 12345 678
**00**4 - 0 12345 678
**01**1 - 0 12345 678
**02**8

### Example #2

If you have say 5 products but each of the 5 has 1 to 9 variations, you can use the first digit to represent 1 of the 5 products and the second digit to represent the variation.

**Product #1**

- 0 12345 678
**10**3 - 0 12345 678
**11**0 - 0 12345 678
**12**7

**Product #2**

- 0 12345 678
**20**2 - 0 12345 678
**21**9 - 0 12345 678
**22**6

**Product #3**

- 0 12345 678
**30**1 - 0 12345 678
**31**8