12-Digit Barcode Check Digit Calculation Example and Explanation

[@earthling3660]

Help. I have a product that was sold in the 70s. It only has 6 numbers under the barcode. Total. I have put this number into a search and cannot get any information. It is on the bottom of a product sold at a US national park. If it helps, this product as well has a sticker that says it was "made in China".

[@gedtoon6451]

The purpose of the check digit is to check that barcode has been read correctly. If the check digit is calculated with only half the digits, the other digits could be corrupted into an incorrect value and we would not know. This is a pretty useless check digit.

[@denshit246]

How about a 13 digit?