1D Barcode Technology: Understanding Types & Applications

1D barcode

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Barcodes play a vital role in the efficient identification, tracking, and management of goods across various industries. 

Among the different types, 1D barcodes, often called linear barcodes, represent some of the most common and widely recognised symbols. These barcodes consist of a series of parallel lines and spaces that encode information in a one-dimensional, horizontal pattern. 

Although newer barcode formats exist, the simplicity and utility of 1D barcodes ensure their continued use in everyday applications. This article will explore what 1D barcodes are, the two primary types of 1D barcodes, common examples, and their practical applications in modern data management. 

What is a 1D Barcode?

Definition of 1D barcode

A 1D barcode, or one-dimensional barcode, is a machine-readable code that encodes data horizontally through a series of parallel lines and spaces. The parallel lines vary in width, representing encoded data as a sequence of binary digits (0s and 1s). The bars and spaces are arranged in specific ratios, such as 2:1, 3:1, or 2.5:1, which determine the relative width of each line.

1D barcodes are capable of encoding only alphanumeric characters and are read from left to right by barcode scanners. Some 1D barcodes feature guard patterns, which are distinctive markers at the beginning and end of the barcode that indicate to the scanner where the data starts and stops. 

1D barcodes are read by various types of barcode scanners, such as laser scanners or camera-based barcode readers, which capture and interpret the pattern to reveal the encoded information. Due to their relatively simple structure, 1D barcodes have a limited capacity, usually 20 characters for encoding information. Therefore, they typically represent numeric identifiers like SKUs, product numbers, serial numbers, or shipping codes

Despite this low data capacity limitation, 1D barcodes are still widely used in retail, logistics, healthcare, and manufacturing due to their reliability and ease of use.

Types of 1D Barcode

1D barcodes can be divided into two main types based on how the encoded data is structured: Discrete Barcodes and Continuous barcodes.

Discrete Barcodes

Discrete barcodes consist of distinct characters separated by non-encoded gaps, known as inter-character spaces. Each character is encoded using the bars, while the gaps simply separate each individual encoded character. Barcode scanners read each character independently, allowing for simpler interpretation.

Because of the inter-character gaps, discrete barcodes are usually larger in size than their continuous counterparts but are often easier to scan and decode. Common examples include Code 11, Code 39, and Codabar.

Meaning and three examples of discrete barcode
Meaning and four examples of continuous barcodes

Continuous Barcodes

Continuous barcodes encode data in a seamless string of characters without gaps between them. Each bar or space forms part of the encoded sequence, and no non-encoded gaps separate the characters. Depending on the barcode symbology used, a set of bars and spaces may represent one or multiple characters.

Due to the continuous nature of these barcodes, individual characters cannot be interpreted separately. This continuous structure enables continuous barcodes to hold more data per unit area than discrete barcodes, resulting in a more compact barcode with higher data density.

Common examples include Universal Product Code, Code 128, Telepen, and MSI Plessey.

What is the Most Common Type of 1D Barcode?

Seven most common types of 1D barcode

Below is a table summarising key information for some of the most commonly used 1D barcodes.

Data Capacity
Character Type
Common Usage
12 digits
Retail product identification, inventory management
13 digits
International retail, supply chain management
Code 128
Variable, no upper limit
Full ASCII set (alphanumeric) and special characters
Shipping industry, logistics, warehouse management, inventory management
Code 39
up to 43 characters
Alphanumeric and special characters
Automotive and defence industry
Interleaved 2 of 5
Variable, no upper limit
Numeric only
Warehousing and shipping, applications
Variable, no upper limit
Numeric, alphabets (a to d only) and special characters
Healthcare, libraries, air freight
Intelligent Mail Barcode
20 to 31 digits
Numeric only
Postal services, bulk mail sorting

Where Are 1D Barcodes Used?

Five industries where 1D barcodes are used

1D barcodes are used extensively across various industries due to their versatility and ease of scanning. Here are some of the primary applications:


1D barcodes like UPC and EAN are heavily used in the retail industry. These barcodes are used for labelling products, enabling quick and accurate scanning at checkout counters to ensure proper pricing and inventory management

Retailers depend on these 1D barcodes to track sales, maintain optimal stock levels, and reduce shrinkage. They also offer valuable insights into customer buying trends.

Warehousing and Logistics

One-dimensional barcodes like Interleaved 2 of 5 and Code 128 are crucial for inventory management, asset tracking, and shipment tracking in warehousing and logistics.

Barcodes on cartons, pallets, and individual items help warehouses streamline sorting and picking processes, reducing errors. Logistics teams utilise these codes to monitor the movement of goods throughout the supply chain, ensuring visibility, timely deliveries and accurate stock counts. 


In healthcare, patient records, medications, and lab samples are often labelled with Codabar and Code 39 barcodes. These barcodes ensure accurate patient identification and medication administration, reducing the likelihood of errors. 

The healthcare industry also uses special barcode symbologies like ISBT 128 barcode to identify and label medical items of human origin, like blood, cells, tissues, and organs.


Manufacturers implement different types of 1D barcodes to label small electronic components and finished products, supporting quality control and inventory tracking. 

Manufacturers can trace items back through the production process by assigning unique codes to individual components and products. This practice improves transparency, reduces defects, and helps with recall management if needed.

Postal Services

Different postal services in different countries employ different 1D barcodes to sort and track mail efficiently. These codes allow postal organisations to route letters and packages quickly and accurately, ensuring that mail reaches its intended destination on time. Bulk mail handlers use barcodes to categorise and manage large quantities of mail efficiently, saving time and labour.

Common postal barcodes include the POSTNET and Intelligent Mail Barcode (used by the United States Postal Service), the Royal Mail 4-State Customer Code (used by the United Kingdom’s Royal Mail), the 4-State Barcode (used by Australia Post), and the FedEx barcode (FDX1D).

Frequently Asked Questions

How to Tell If a Barcode Is 1D or 2D?

You can identify a barcode as 1D or 2D by visually inspecting it. 1D barcodes consist of parallel lines and spaces arranged horizontally, while 2D barcodes feature patterns of squares, dots, or other shapes arranged both horizontally and vertically.

What Is the Difference Between 1D Barcodes and QR Codes?

A 1D barcode is a linear, horizontal code that encodes data using lines and spaces. A QR code is a type of 2D barcode that encodes data both horizontally and vertically using square or rectangular modules.

Can Phones Scan 1D Barcodes?

Smartphone cameras cannot directly scan 1D barcodes. However, specialised barcode scanning apps can capture images of 1D barcodes and decode them.

Can a 2D Barcode Scanner Read 1D Barcodes?

Yes, most 2D barcode scanners can read 1D barcodes. 

The Bottom Line

1D barcodes continue to serve as essential tools across various industries, from retail and logistics to healthcare and manufacturing. Their linear structure and ease of scanning make them ideal for labelling products, managing inventory, and tracking shipments. 

Although newer barcode formats like two-dimensional barcodes offer greater data capacity and error correction features, 1D barcodes remain relevant due to their reliability, cost-effectiveness, and widespread compatibility. 

We hope this article was useful. 

Thanks for reading! 

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