How Does a UPC Code Work

Photo of UPC code

I don’t know if many folks out there have given much thought to how the inventory at you favorite merchant is tracked. But nearly everything on the market today is labeled with an inventory tracking label called a Uniform Price Code, or generally referred to as a UPC or Barcode. So I thought it would be cool to go over what a upc label was and how it worked.

What is a UPC Code

A UPC code is a series of fifty-nine alternating black and white lines. Each of these lines are different widths and the lines correspond to twelve different numbers when they’re read by an optical scanner.  These numbers are the same ones that appear below the code on the label. Each of the twelve numbers are represented by a set of four lines.  Meaning two that are white and two that are black. Plus on each end of the code are three lines, and the middle has five lines.  These sets of lines act as standards for the code.

How does a UPC Code Work

The manufacturer of the product are represented by the first six numbers of the code. Followed by the next five lines in the series that represent the product’s number.  Then you’re left with the last digit which is called a “check digit”.  This digit must match a mathematical calculation that is done by the scanner by using the first eleven digits. If this calculation doesn’t end with the proper result, then it is considered a mismatch and the process must be repeated with a rescan.

Although this code tag does contain a bunch of information about the product, the one thing it doesn’t include is the price of the item. The price for the item is stored on the merchants computer, either entered by their home office, or by the stores inventory control department. So basically when the product is scanned, the scanner tells the computer what the product number is and the computer sends back the corresponding price for that product.

How do Store Bonus “Rewards” Cards Work

Store bonus cards, sometimes called rewards cards work in a bit of a different manner. Photo of Store Rewards CardFirstly they have more digits than a UPC code does. Not only that, but they are not designed for product use, they are used to track the purchases a specific customer is making. This way they can give rewards to customers based on how much they have spent and or how often they frequent the establishment.

In some known cases, police officials have been known to use this information in obtaining arrest warrants on criminals. They base these warrants on suspicious buying patterns. In Pennsylvania there was a man that was arrested by police for purchasing a not so normal amount of red tip matches.  The supermarket contacted police after noticing how many of these showed up on his rewards card. Evidently these were red phosphorous matches which were on the “hot list” of suspicious items that is sent out to merchants by police officials. They were being used to manufacture methamphetamine, and the police used this information to obtain a search warrant and make the arrest, shutting down his lab.

So there ya have it. A little bit of information you may not of known about UPC codes and rewards cards. So next time you visit your supermarket to purchase groceries or use your rewards card at your favorite department store, you’ll know the inner workings of all that technology. Happy Shopping!

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9 thoughts on “How Does a UPC Code Work
  1. nice info, never thought about that, always think it was all random, depending on product.

    1. Yep, it’s amazing the technology that is available these days. UPC codes have really revolutionized the industry standard for keeping track of inventory.

  2. Great Article – In the Auction business we used to use lot tags with written numbers – I have just changed to UPC labels which keep track of the assets throughout the whole sales process. Now we can take pictures with special camera that will scan upc code and change the filename automatically. TECHNOLOGY is so great –

    1. Wow! That’s really amazing how easy something as simple as a barcode can make business. I bet you are really enjoying the benefits of having that system in place. How did you live without it, eh? 😀

  3. Interesting article.especially the second one,but i am just curious as how frequently reward card information is used by police to track there any use of this information for the merchants as well?
    secondly are they keep rocord of every item or specific items only?

    1. I’m pretty certain that the police would only use this information in the event someone was thought to be committing a crime by means of the business establishment.

      As far as what they track. At the store level it would vary depending on the merchant. But normally a rewards card will track all purchases made, but only if you allow them to scan your card before purchase. Otherwise there would be no means to track your purchases.

  4. Great post, Robert! I deal with barcodes on a daily basis, but there’s a lot about them that I just didn’t know! They’re not only handy for product codes, but can be quite useful in a variety of other situations. We use them in the office to automate document indexing when scanning large batches of files simultaneously. It really speeds up the paper archiving process!

    1. Very interesting application, indexing files that is. I bet that would make short work of a huge pile of papers. I never really thought of using barcodes in that way. Thanks for the added information!

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