Introduction

If you're selling an item without a barcode—like a local or specialty product—you’ll need to create a custom UPC to use it in Passport. The last digit in a UPC, called the check digit, must be calculated correctly for the code to work.

UPC Check Digit Calculator

Step-by-Step Instructions

1. Start with an 11-digit number that will be your custom UPC (e.g., 810012110099).
2. Add the digits in the odd positions (1st, 3rd, 5th, etc.), excluding the final digit:
   1. Example: 8 + 0 + 1 + 1 + 0 + 9 = 19
   2. Multiply the result by 3 → 19 x 3 = 57
3. Add the digits in the even positions (2nd, 4th, 6th, etc.), excluding the final digit:
   1. Example: 1 + 0 + 2 + 1 + 0 = 4
   2. Add this to the previous total → 57 + 4 = 61
4. Divide the total by 10 and find the remainder → 61 ÷ 10 = 6 remainder 1
5. Subtract the remainder from 10 → 10 - 1 = 9
6. The check digit is 9, making the full UPC: 8100121100999