This article shows you how to calculate and add the correct check digit to an 11-digit custom UPC so you can make sure items without barcodes scan correctly in Passport.

UPC Check Digit Calculator

Before you begin

• You are using the Passport POS.
• The item does not have a manufacturer barcode.
• You already have an 11-digit base number you want to use as your UPC.

Steps

1. Start with an 11-digit number that will be your custom UPC (for example: 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
3. Multiply that total by 3.
   1. Example: 19 × 3 = 57
4. Add the digits in the even positions (2nd, 4th, 6th, etc.), excluding the final digit.
   1. Example: 1 + 0 + 2 + 1 + 0 = 4
5. Add this number to the previous total.
   1. Example: 57 + 4 = 61
6. Divide the total by 10 and find the remainder.
   1. Example: 61 ÷ 10 = remainder 1
7. Subtract the remainder from 10 to get the check digit.
   1. Example: 10 − 1 = 9
8. Add the check digit to the end of your original number.
   1. Final UPC: 8100121100999

Tips & Warnings

• The check digit must be correct, or the barcode will not scan.
• Always calculate the check digit before adding the UPC to Passport.
• If an item does not sell after scanning, double-check the UPC math.
• Use a calculator to reduce mistakes if working with many UPCs.
• Keep a short list of custom UPCs to avoid duplicates.