What is Barcode Symbology?

There are many different types of barcodes, which are called Symbologies. They vary by the amount and type of encoded data (e.g., numeric only or alphanumeric). A Symbology is a defined method of representing numeric or alphabetic digits using bars and spaces that are easily scanned by computer systems. (i.e. - a specific type of barcode).

Typical characteristics of a Symbology: X-dimension: size of the smallest bar or space represented in 1/1000 of an inch  (i.e. 15 mil symbol).

When you breakdown the DNA of a barcode, character sets are combinations of bars and spaces that represent a specific character. X Dimension is the width of the smallest bar or space element in the barcode which is also referred to as mil size (1 mil = .001 inch). Quiet zones are the areas just before and after the barcode.

Graphic showing the quiet zones, character sets and x-dimension elements of a barcode

Barcodes are divided into two main types: one dimensional (1D) and two dimensional (2D).

What Types of Barcode Symbologies are there?

1D and 2D Symbologies do differ and therefore support different types and amounts of data. The type of barcode that is being used in the application environment will impact the type of scanner that is needed to read it.

1D Symbologies encode data horizontally along the barcode and can store a limited amount of information (around 85 characters maximum but typically much less, depending on the code type). As more data is encoded, the barcode becomes wider.

1D Barcode Symbology examples include UPC-A (Data capacity of 12 numeric digits - 11 user specified and 1 check digit), UPC-E (Data Capacity of 7 numeric digits - 6 user specified and 1 check digit), Code 128 (Variable length alphanumeric data) and I 2 of 5 (Variable length numeric data).

2D Symbologies have a two-dimensional way of representing data – both horizontally and vertically – and can store a greater amount of information (hundreds of characters), in a much smaller space, compared to a 1D code. As more data is encoded, the size of the barcode can be increased in both the horizontal and vertical directions, thus maintaining a manageable shape for easy scanning. To properly decode the data, a scanner must read the entire symbol, in both dimensions.

Examples include Data Matrix (Consists of any type of data including binary or alphanumeric and be up to 3116 bytes in length), Aztec (Consists of any type of data including binary or alphanumeric and be up to 3750 bytes in length), Maxicode (Holds up to 93 alphanumeric characters or 138 numeric digits) and QR Code (Consist of any type of data including binary or alphanumeric and be up to 7089 bytes in length).

Determining the best barcode symbology depends on the type and amount of data required, and the marking space available. The same symbology is not required for all items, because barcode scanners can recognize and decode multiple barcode formats.

Below is an overview of the main symbologies:

GS1 Databar Codes

The GS1 Databar family consists of 1D Codes and are commonly used to label fresh foods.  The type of data commonly encoded includes information such as an item’s batch number or expiration date, or item weight.

UPC & EAN (Universal Product Code / European Article Number)

UPC & EAN (Universal Product Code / European Article Number)

Universally recognized, the UPC or EAN barcode is the most commonly used in the retail market – printed on nearly every consumer product in the world. The data is numeric only.


Code 128 barcode

Code 128

One of the densest linear symbologies, encodes the full 128-character ASCII character set. Often used to include information like serial numbers and expiration dates, making it a good candidate to track items through global supply chains.

Code 39 Barcode

Code 39

Also called Code 3 of 9, it is one of the oldest and most widely used symbologies. It is a variable-length alphanumeric symbology for encoding 26 capital letters plus numerals and seven special characters. An extended version is available that supports all 128 ASCII characters. Code 39 is less dense than Code 128, thus requiring more room on the label.

Data Matrix Barcode

Data Matrix

A 2D symbology, Data Matrix is commonly used to mark small items as it can encode a significant amount of information in small space  and is often used in  pharmaceutical applications, or other operations where tracking and tracing is critical.

Aztec barcode example


A 2D matrix symbology containing from 13 to 3,832 numeric characters or 12 to 3,067 alphabetic characters. Aztec Mesas are Aztec Code-based supplements that enable linear barcode symbols to encode additional information. The resulting symbol is a composite of linear and 2D symbologies.

QR Code example

QR Code

This stands for Quick Response Code and is a 2D code containing 4000 – 7000 Characters. These are commonly used for mobile barcoding applications, such as loyalty cards or coupon codes.

PDF417 Barcode


PDF417 is a stacked linear or two-dimensional barcode. It is commonly recognized as the barcode on many U.S. Driver’s Licenses, but can also be used for other applications related to transportation or inventory management. Data is encoded in both the horizontal and vertical dimensions. As more data is encoded, the size of the barcode can be increased in both the horizontal and vertical directions thus maintaining a manageable shape for easy scanning.

Where are Different Symbologies used?


1D Numeric Codes:Popular Applications
I 2 of 5:
Most Retail Products in US - High Volume Scanning
International Retail Products
Shipping, Laboratories, Warehouse, Industrial Apps
Libraries, Blood Banks, Overnight Package Delivery
1D Alpha-Numeric Codes: 
Code 128:
Code 39: 
Identification, Inventory, Tracking
2D Codes: 

Data Matrix:


QR Code: 
File Driver’s Licenses and other Identification cards, boarding passes, inventory
Pharmaceuticals, Circuit Boards, Surgical Instruments, Manufacturing S/N
United Parcel Service – Package Sorting
Order Confirmation, Mobile Loyalty & Coupons

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