How to Decode a Barcode Algorithm

By Veronica Summers

Decode a barcode by analyzing the series of numbers within the code.
i pencil and barcode image by Anatoly Tiplyashin from

Virtually every product you buy in a retail establishment has a barcode or UPC symbol as of 2011. Barcodes are black and white lines of varying widths followed underneath by a series of numbers. You can find barcodes on price tags or on the bottom of most boxes. Retailers and suppliers use barcodes to track an item's manufacturer, the item type and item serial number. Retailers use scanners to read the barcode and charge you the correct price. Because lines on the bar code are read by computer scanners, the easiest way to decode a barcode with your eyes is to analyze the corresponding numbers under the bar code.

Step 1

Find the barcode on the item. Look on the price tag, side or bottom of the item for the black and white lined graphic.

Step 2

Examine the first digit. This specifies the product category. The number zero is the most common digit and specifies a grocery item. For example, the number zero is used on a cereal box, a cola can or a loaf of bread.

Step 3

Look at the next five digits. This number is a unique number that specifies the manufacturers name. For example, the number 49000 belongs to the Coca Cola Company.

Step 4

Move to the next five digits. This set defines the specific type of product. For example, 00658 belongs to 12 oz. cans of Diet Coke. Two-liter bottles of Diet Coke would have a different number.

Step 5

Look at the last digit. This is a testing number used by the computer scanners to verify that their scanning was correct.

Step 6

Access the Internet and navigate to an online UPC database such as UPC at "" or simply enter the bar code in a search engine like Google or Bing. These websites will decode the bar code for you and display detailed company and product information.