An Electronic Product Code (EPC) is a unique number stored on an RFID tag that identifies a specific individual item, not just a product type. Think of it as a serial number for every single physical object in a supply chain. While a traditional barcode tells a scanner “this is a box of cereal,” an EPC tells the scanner “this is box of cereal number 4,817 from this particular production run, made by this company.” That level of specificity is what makes RFID-based tracking so powerful.
The Four Parts of an EPC
Every EPC is built from four segments that work together like a mailing address, moving from broad to specific:
- Header: A short code (8 bits in the standard 96-bit format) that tells the reading system which type of EPC scheme is being used and how to interpret the rest of the number.
- Manager Number: Identifies the company or organization responsible for the item. GS1, the global standards body behind EPCs, assigns each manager number and ensures no two companies share the same one.
- Object Class: Identifies the type of product. A company might assign one object class to a particular style of shoe and another to a different style. These numbers only need to be unique within that company’s manager number.
- Serial Number: The truly individual piece. This number is unique within each object class, meaning every single item rolling off a production line gets its own serial number. No two items of the same product type share one.
A full EPC in its human-readable form looks something like this: urn:epc:id:gid:95100000.12345.400. The first number is the manager (company), the second is the object class (product type), and the third is the serial number (individual item).
How EPCs Are Stored on RFID Tags
On the actual RFID chip, the EPC is stored as a binary string, a sequence of ones and zeros. The most common format uses 96 bits, which was for years the largest memory size available on passive RFID tags. A 96-bit EPC can encode an enormous number of unique identifiers, but it comes with some restrictions. Serial numbers in this format must be all-numeric, can’t have leading zeros, and must fall within a certain value range.
Newer tags support longer encodings that remove those restrictions entirely. For example, a Serialized Global Trade Item Number (SGTIN), one of the most common EPC types used in retail, allows serial numbers up to 20 alphanumeric characters when encoded beyond 96 bits. The 96-bit version remains widely used because it’s compatible with older hardware and covers most practical needs.
When a reader scans an RFID tag, it picks up this raw binary data. Software then translates that binary string into a readable format, either a standard URI or a GS1 Digital Link that can point to product information on the web. The latest version of the GS1 Tag Data Standard (version 2.3, released in October 2025) added new encoding schemes that let an RFID tag carry domain name information alongside the EPC, making it possible to decode the tag directly into a web address.
How EPC Differs From a Barcode
A standard UPC barcode identifies a product at the class level. Every can of the same brand of tomato soup on a grocery shelf has the same barcode. This means a store’s inventory system knows it has “some cans of tomato soup” but can’t distinguish one can from another.
An EPC adds serial-level identification. Each can gets its own unique number. This distinction matters because it enables automated, item-level inventory counts without someone physically scanning each product. RFID readers can detect hundreds of tagged items per second from several feet away, through boxes, without line of sight. Research from the University of Arkansas RFID Research Center found that RFID-enabled systems improved inventory accuracy by more than 27 percent over a 13-week period. Understock situations dropped by 21 percent, and overstock (where the system shows less inventory than actually exists) decreased by 6 percent.
Who Manages the EPC System
EPCglobal, a division of GS1, develops and maintains the standards behind the Electronic Product Code. GS1 is the same organization responsible for the barcodes found on virtually every consumer product worldwide. When a company subscribes to the EPC system, it receives a unique manager number and gets registered in the Object Naming Service (ONS), a directory that links EPC manager numbers to company information.
The communication standard that governs how RFID readers talk to EPC-tagged items is called the EPC UHF Gen2 air interface protocol. First published in 2004, it defines how passive RFID tags operating in the 860 to 930 MHz range exchange data with readers. Gen2 has become the dominant standard for passive UHF RFID (sometimes called RAIN RFID) and is used across retail, logistics, healthcare, and manufacturing.
Where EPCs Are Used in Practice
Retail is the most visible application. Major retailers use EPC-tagged items to run rapid, store-wide inventory counts that once took overnight shifts with handheld barcode scanners. Staff can walk through a store with a mobile RFID reader and capture the location and identity of thousands of items in minutes. This makes it practical to do inventory counts weekly or even daily instead of quarterly.
In supply chain logistics, EPCs let companies track individual pallets, cases, or items as they move through warehouses, onto trucks, and into stores. Because each item carries a unique identity, the system can flag exactly which items arrived, which are missing, and which ended up in the wrong location. Pharmaceutical companies use EPCs to comply with drug serialization laws that require tracking every individual package from manufacturer to pharmacy. Airlines tag luggage with EPC-enabled tags to reduce lost bags. Libraries use them for self-checkout and rapid shelf auditing.
The core value across all these applications is the same: the EPC gives each physical object a globally unique digital identity, turning it from an anonymous item into something a computer system can track, locate, and manage individually.