Barcode facts for kids

Kids Encyclopedia Facts
A UPC-A barcode symbol

A barcode is a way of storing numbers printed in a way that a computer can easily read. The first barcodes stored the numbers using lines (bars).

Wikipedia barcode 128
The word Wikipedia represented in a barcode

The first use of barcodes was to label railroad cars, but barcodes were not a big success until they were used in supermarket checkout systems. The first product that used a barcode was a pack of Wrigley's Juicy Fruit Gum sold on June 26, 1974. Barcodes are now used for many purposes.


Norman Joseph Woodland and Bernard Silver developed the modern barcode, and were granted a patent for it in 1952. The idea was to make the checkout of articles easier, using a code which was inspired by Morse code. In 1959, David Collins developed a system for tracking railroad carriages which used barcodes. This system had a problem, because it could not handle dirt on the barcodes easily. In the 1970s, the system was abandoned, but in the 1980s, a similar system which used radio tags was introduced.


There are different barcode types, which use different designs:

  • The first designs used the width and spacing of lines; these types are known as one-dimensional barcodes. Examples are the European Article Number or the Universal Product Code.
  • Some designs use two dimensional codes. In these codes, dots that are either white or black are used. Such codes can store more information than one-dimensional codes. Examples are the Secure Quick Response Code, Aztec Code, BeeTagg or RMS4CC.

The standard barcode uses changes in lines and spaces to store numbers in a code that computers can read. The lines are read by a scanner and changed into numbers. It is designed that it can be read forwards or backwards, so the user does not have to be careful how a product is put in front of the reader. A laser line can be used to scan (read) the changes. The laser scanners are also called barcode readers. Since this laser line scans in one direction (left or right), this is called a 1D barcode.

Newer 2D systems use symbols other than bars and can hold more information, but they are also called barcodes. They need to be scanned left or right, and up or down (two directions). These can also be read from an image by special software. Smart phones can have an app to read some of these 2D systems from a picture, particularly QR codes. This is becoming increasingly popular as more apps are able to utilise such features to help the user obtain access to websites and special resources, such as being used in 'digital cities', such as Bordeaux.


Barcodes — especially the Universal Product Code, UPC — have slowly become an important part of modern life. They are used in many places, and the technology is constantly improving. Some modern uses of barcodes are:

  • Almost everything bought in a store has a SKU using a UPC barcode on it. This greatly helps in keeping track of a large number of items in a store.
  • They are used to identify patients in a hospital, helping doctors and nurses track patients and their medical history.
  • The tracking of things that move, including rental cars, airline luggage, railroad cars, nuclear waste, and mail.
  • Since 2005, airlines have used a 2D barcode on boarding passes.
  • Entertainment tickets can have barcodes to enter sports arenas, cinemas, theatres, fairgrounds, etc.


In sales, the use of barcodes can provide up-to-date information to help the business. For example:

  • Things that are sold can be ordered before the store runs out of them.
  • Changes in price can be updated one time in the computer, so the cashier doesn't need to look it up or remember what's on sale.
  • Products can be tracked over time, to predict seasonal changes in demand.
  • When used on a company card used by shoppers, the company can track the buying patterns of shoppers.

Example images

Images for kids

Barcode Facts for Kids. Kiddle Encyclopedia.