Barcodes 101: A Complete Guide to Learn About Barcode Technology


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Have you ever wondered what those square or rectangular boxes with black or blue lines are on the labels or packaging of various products? Or have you noticed how a retailer scans these lines before they sell the products? Well, those small black or blue lines are called Barcodes.

Barcodes are an amazing invention that has revolutionized the way businesses operate. They have become an essential part of the modern supply chain.

In this article, we’ll give you an in-depth crash course on barcodes. We will start by explaining what a barcode is, how it represents data, and how it works.

Then, we will cover the anatomy of a barcode symbol and list some common types of barcodes. Finally, we’ll discuss the benefits and drawbacks of using barcodes and answer some common questions.

So, without further ado, let’s get started.

What is a Barcode?

Barcodes are machine-readable representations of data often printer by thermal printers and read by barcode scanners.

A barcode consists of a series of parallel black or blue lines generally printed in a square or rectangular box with a white or transparent background.

The parallel lines represent binary digits 0 and 1, which are used in a sequence to represent numbers from 0 to 9. These parallel lines have different widths, spacings, and sizes depending on the data they represent.

A barcode only stores product-related information. This includes.

  • Date of manufacturing
  • Expiry date
  • Name of the manufacturer and supplier
  • Country of origin
  • Price
  • Quantity

Barcodes generally have numbers printed beneath parallel lines. These numbers are the same values that are encoded in a barcode. Therefore, if barcode labels become unreadable, users can manually enter the numbers to retrieve the data from the database.

How Does a Barcode Represent Numbers Between 0 and 9?

Barcodes Representation of Numbers 0 to 9

Each barcode digit is represented by seven equal-sized vertical blocks containing parallel lines and spaces. In other words, each barcode digit is allotted the same amount of horizontal space, i.e. exactly seven units.

Therefore, to represent numbers between 0 to 9, each of the seven blocks is coloured with a different pattern of black and white stripes.

For example, the number 0 is represented by colouring three white stripes, two black stripes, one white stripe, and one black strip. Similarly, number 3 is represented by one white stripe, four black stripes, one white stripe, and one black strip.

How Does Barcode Works?

Barcodes are read by a special device called a Barcode Scanner. Barcode scanners have laser and optical sensors that can decode a barcode.

Here’s how a barcode gets deciphered.

  1. A barcode scanner sends a beam of light (usually red) of a particular frequency to sweep across the barcode.
  2. The barcode absorbs some of the light and reflects the rest. This is the reason behind using the back or blue and white or transparent background in a barcode. The black or blue lines absorb the light, whereas the white or transparent background reflects the light toward the scanner.
  3. The reflected light returns in a pattern, depending on the shape and width of the black or blue lines. This patterned light is captured by an optical sensor in the scanner, which converts it into electronic signals.
  4. The scanner transfers the electronic signals to a computer that parses the data and decodes it. After decoding, the computer uses the information and retrieves data from a database, displaying the product information on the screen.

The above process is completed in nanoseconds and happens without any human interference. This amazing technology has simplified how products are sold, purchased, and tracked throughout the supply chain.

Now that you know what a barcode is and how it works let’s learn the barcode anatomy.

Barcode Components

Components of Barcode

A bar code symbol has four components.

  • Quite Zone (Margin)
  • Start/Stop Character
  • Data Characters
  • Check Digit (Checksum Character)

Quiet Zone

Quiet Zone is the margin at either end of a barcode. It represents a minimum margin requirement between the outermost bar of one barcode and the first bar of the next successive barcode.

Ideally, the minimum quiet zone should be 2.5 mm. If the quiet zone is smaller than 2.5 mm, barcodes are difficult to scan.

Start/Stop Character

Start/Stop characters represent the beginning and end of the barcode data.

Start/Stop characters differ based on the type of barcode used. For example, Code 39 uses “*” as a start and stop character, while Codabar uses letters “a”, “b”, “c”, and “d” as start and stop characters.

Data Characters

Data characters are the barcode information fields in which data is encoded through a series of bars and spaces.

Check Digit

Check digit, also known as the Checksum character, is a single digit that validates and verifies the accuracy of a barcode.

The check digit is mathematically calculated based on the digits in the data characters. It can be any number between 0 and 9. The check digit is sometimes represented as X, which indicates the number 10.

Type of Barcodes

Barcodes are broadly divided into two categories.

  • Liner or 1D Barcodes
  • Two Dimensional or 2D Barcodes

Liner or 1D Barcodes

Linear barcodes, also known as one-dimensional (1D) barcodes, store data horizontally and contain a sequence of vertical lines of varying widths. Linear barcodes have numbers, letters, and symbols that link the code to a database containing product information.

Some popular types of linear barcodes include Code 39, Code 128, Interleaved 2 of 5, and Universal Product Codes (UPC).

Two Dimensional or 2D Barcodes

Two-dimensional barcodes store data both horizontally and vertically. 2D barcodes use graphics or patterns like dots, squares, or hexagons, which keep more data in less space. They are also called matrix barcodes or micropattern codes.

Some of the most popular types of 2D barcodes include Datamatrix, QR Code, and Aztec Matrix.

10 Common Types of Product Barcode Symbologies

There are several types of barcodes, each with a different storage capacity, application, and unique benefits and drawbacks. Let’s look at the ten most popular product barcode symbologies used today.

1. UPC Barcode

UPC-A barcode

UPC stands for Universal Product Code. It is a liner barcode. UPC primarily identifies and tracks products throughout the supply chain, from manufacturing to distribution and sales.

UPC barcodes are of two types.

  • UPC-A – It consists of 12 numerical digits.
  • UPC-E – It consists of 6 numerical digits.

Please note that UPC does not contain any alphabetic letters or symbols.

2. EAN Barcode

EAN - 13 barcode

EAN stands for European Article Number. It is a liner barcode. The EAN barcode is similar to the UPC barcode and is used to track and identify products in the same way. The only key difference between the two barcodes is that UPC is widely used in the US, while EAN is used in Europe.

EAN barcodes are of two types.

  • EAN-13 – It consists of 13 numerical digits.
  • EAN-8 – It consists of 8 numerical digits.

Please note that EAN does not contain any alphabetic letters or symbols.

3. Code 39

Code 39 barcode

Code 39 is a full alphanumeric linear barcode that can contain letters, numbers, and special characters. It is one of the most popular barcodes in identification systems, such as inventory tracking and product management.

The name Code 39 comes from the fact that it can only hold a maximum of 39 characters. However, in a recent update, the character limit of Code 39 is increased to 43.

Code 39 has been adopted as a military standard of the US Department of Defense.

4. Code 128


Code 128 is an advanced version of Code 39. It is a high-density liner barcode defined in ISO/IEC 15417:2007 standards. Code 128 is widely used in shipping and packaging industries to track, identify, and manage containers and pallets.

Code 128 is capable of encoding all 128 characters as per the ASCII (American Standard Code for Information Interchange). It can hold 232 characters, including the start and end codes.

Code 128 is of three types.

  • Code 128A – It encodes ASCII characters 00 to 95, special characters, and FNC (Function Code) 1–4.
  • Code 128B – It encodes ASCII characters 32 to 127, special characters, and FNC 1–4
  • Code 128C – It encoded numeric data character pairs from 00 to 99 and FNC1.

5. Interleaved 2 of 5

Interleaved 2 of 5 barcode

Interleaved 2 of 5 is a liner barcode that contains a high density of bars. It can encode numeric data (0-9) only. Interleaved 2 of 5 always have an even number of digits.

Interleaved 2 of 5 is commonly used in manufacturing, shipping and warehouse industries to track pallets, crates, boxes, and other types of containers.

6. Codabar

Codabar Barcode

Codabar is one of the earliest types of liner barcodes. It is also called Code-A-Bar, Ames Code, NW-7, Monarch, Code 2 of 7, Rationalized Codabar, ANSI/AIM BC3-1995, or USD-4.

Codabar can encode numerals (0 to 9) and symbols (“-“, “$”, “:”, “/”, “+”, and “;”). It has a maximum capacity of storing 32 characters (including the starting and ending characters).

Codabar is widely used in libraries, US blood banks, and overnight package delivery industries.

7. GS1 DataBar

GS1-DataBar barcode

GS1 DataBar, also known as RSS or Reduced Space Symbology, is a POS (point-of-sale) linear barcode that was adopted by GS1 in January 2011. It is a new generation of the UPC/EAN code family.

GS1 DataBar encodes only numerical digits (0 to 9). It is capable of carrying manufacture’s GTIN-12 or GTIN-13 in 14-digit data format. It supports different types of encoding, such as stacked and omnidirectional.

As GS1 DataBar can hold information like expirations date, lot numbers, and batch codes, it is commonly used to manage and track inventory in the food and healthcare sectors.

8. QR Code

QR Code type of Barcode

QR code, also known as Quick Response Code, is a two-dimensional barcode. It uses small black-and-white square and rectangle patterns to store information. It was invented in 1994 by Denso Wave, a subsidiary of Toyota Motor Corporation.

QR code is capable of encoding all types of data (numerical digits, alphabets, Kanji characters, and binary codes). It usually contains a locator, identifier, or tracker that takes the users to a website or application.

Due to their ability to store a large amount of information(more than 7,000 numbers or 4,000 alphabets), QR code is commonly used in advertising and promotional campaigns.

Check out our article on QR code vs Barcode to know the difference between these two types of barcode symbologies. 

9. Datamatrix

Data Matrix

Datamatrix is a 2D barcode that contains small black and white square or rectangular cells arranged in a matrix pattern. It can store up to 2,335 alphanumeric characters and is capable of encoding all standard ASCII characters.

Datamatrix has exceptional error correction algorithms, meaning that a scanner can read and recognize the barcode’s data even if 30 per cent of the pixels are damaged.

Datamatrix is commonly used in the healthcare, automotive, and electronics manufacturing industries.

10. PDF417

PDF417 barcode

PDF417, also known as Portable Data File 417, is a two-dimensional barcode that contains multiple stacked linear rows. It is capable of encoding numerical digits, alphabets, Kanji characters, and binary codes. PDF417 is defined in ISO/IEC 15438:2015.

PDF417 is commonly found on hazardous materials identification labels, airline tickets, visas, healthcare records, and ID cards.

The Department of Homeland Security adopts the PD417 barcode as the machine-readable zone technology for state-issued identification cards and RealID-compliant driver’s licenses.

Benefits of Barcode

Barcode technology is used in almost every industry, including retail, healthcare, logistics, and food and beverage. Here are some of the key benefits of barcode technology.

Improved Inventory Management

Barcode technology allows retailers and warehouses to track and manage their inventory accurately.
By scanning items in and out as they’re sold or received, businesses always know exactly how much stock they have on hand. This ensures they always have the right amount of products on their shelves and avoid losing out on revenue by overstocking or running out.
Moreover, barcodes help retail stores track which products are selling well and which ones aren’t. This allows retail stores to make better decisions about purchasing and discounting products, preventing obsolete inventory.

Real-Time Data Tracking

Each time a barcode is scanned, the data, such as the product’s name, description, and price, is sent to the company’s enterprise resource planning (ERP) or business management system.

This data allows businesses to track and analyze important metrics such as sales volume, the average amount of goods sold, inventory turnover, average transaction value, and inventory value in real time. Businesses can use this data to make better decisions regarding marketing campaigns and improve their operations.

Eliminates Human Error

When a product reaches different points in the supply chain, information such as the product’s weight, price, and shipping destination needs to be entered manually.

Manual data entry is prone to human error, such as typos. Such data entry errors often lead to billing problems, mismanaged inventory, price disputes, and other issues down the line.

With barcodes, employees no longer have to manually enter product data into a system; all they need to do is scan the barcode and let the system do its job. This eliminates human errors and ensures that information is transferred accurately and efficiently between different points of the supply chain.

Fast and Efficient Checkout Process

Barcodes are scanned much quicker than manually entering data so that transactions can be completed much faster. This is especially beneficial during peak hours when there are long lines of customers waiting to check out.

Moreover, barcodes allow customers to scan items at a self-checkout counter, eliminating the need to queue up and wait for a cashier. This improves customer experience and satisfaction, leading to higher sales and a better store reputation.

Reduce Employee Training Time

Scanning barcodes is a self-explanatory process and does not require a lot of training or technical skills. This eliminates the need to train employees to use complex scanning software, manage databases or memorize product names or numbers.

As a result, new employees can start scanning products and carrying out transactions immediately after being hired.

Drawbacks of Barcode

Despite the benefits of barcodes, there are some drawbacks that businesses be aware of before implementing them in their operations.

Here are a few of the disadvantages of using barcodes.

Vulnerable to Damage

Barcodes are susceptible to damage like scratches, smudges, or cuts while handling the product. Barcodes also get damaged by exposure to harsh weather conditions like rain or direct sunlight.

Once a barcode gets damaged, it becomes unreadable by the scanning system and will need to be replaced. This causes delays and operational downtime, which has a negative impact on the business.


Barcodes require hardware (like printers, computers, and barcode scanners) and software (like database management, asset tracking software and barcode generators) to operate. This requires a significant upfront investment and can be cost-prohibitive for smaller businesses.

Moreover, hardware like barcode scanners requires regular maintenance, such as cleaning or replacement of parts, to continue operating efficiently. Such maintenance costs can be a burden for businesses in the long run.

Labour Intensive Process

Businesses require human employees to create, print, and affix barcodes on each product. This is a labour-intensive and time-consuming process, especially if the business has a large inventory.

Moreover, employees will require significant training and supervision for creating, printing, and affixing the barcodes. This can increase operational costs and prevent the business from focusing on its core operations.

Frequently Asked Questions

Who Invented the Barcode?

The barcodes were invented by Norman Joseph Woodland and Bernard Silver.

What Information is Stored on a Barcode?

A typical barcode stores product-related information like product name, manufacturer & supplier name, price, and country of origin.

However, depending on the type of barcode (1D or 2D) and barcode symbology (like EAN, QR code), more information like stock keeping unit (SKU) can be added to a barcode.

How do You Scan Barcodes? or What Device is Used to Read a Barcode?

Barcodes are scanned using a device called Barcode Scanner or Barcode Reader.

Nowadays, barcodes can also be scanned using smartphones.

How is Bar Codes Generated?

Bar codes are generated using special software called Barcode Generators. These software allows users to choose the bar code symbologies and encode product-related information in the bar codes.

Barcode generators are typically included in the label design and printing software. Check out our article on the best label printing software. 

How Much Information Can a Bar Code Hold?

The amount of information a bar code can hold depends on the type of bar code and the symbology used.

For example, a 1D bar code such as Code 39 stores 43 characters. On the other hand, 2D bar code like QR codes stores more than 7,000 numbers or 4,000 alphabets.

In general, 2D barcodes store more information than 1D barcodes.

Do Bar Codes Need to be Registered?

No, bar codes do not need to be registered.

What Type of Bar Code do Retail Stores Use?

Generally, retail stores use UPC (Universal Product Code) barcodes.

Final Thoughts

Overall, barcodes are incredibly useful and help with inventory control, streamlining transactions, and more.
While they have some drawbacks, such as vulnerability to damage or high costs, the benefits of barcodes far outweigh these disadvantages.
We hope this comprehensive barcode guide has helped you learn more about this amazing technology. If you have any questions or comments, please feel free to reach out to us.

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