Do RFID Tags Need to Be Pre-Encoded? A Guide for RFID Buyers
Not every RFID tag needs to be pre-encoded before delivery. Some applications use blank tags and encode them after installation, while others require each tag to arrive with a unique EPC or other predefined data. Choosing the right encoding method can affect production efficiency, inventory management, traceability, and system integration. In this guide, we explain when RFID tags should be pre-encoded, what information can be written to the tag, how buyers should prepare encoding data, and what to confirm with an RFID tag supplier before placing an order.
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7/1/20266 min read
Do RFID Tags Need to Be Pre-Encoded? A Guide for RFID Buyers
Introduction
Not every RFID tag needs to be pre-encoded before delivery. Some applications use blank tags and encode them after installation, while others require each tag to arrive with a unique EPC or other predefined data. Choosing the right encoding method can affect production efficiency, inventory management, traceability, and system integration. In this guide, we explain when RFID tags should be pre-encoded, what information can be written to the tag, how buyers should prepare encoding data, and what to confirm with an RFID tag supplier before placing an order.
1. What Does “Pre-Encoded RFID Tag” Mean?
A pre-encoded RFID tag is an RFID tag that has data written into its memory before it is shipped to the customer.
For UHF RFID tags, this commonly means writing a specific EPC value into the EPC memory during production or before shipment.
For example, a customer may require a batch of 10,000 tags with unique EPC numbers:
Tag 001: EPC 0001234567890001
Tag 002: EPC 0001234567890002
Tag 003: EPC 0001234567890003
...
Tag 10,000: EPC 00012345678910000
The exact data structure depends on the customer's RFID system and encoding requirements.
Pre-encoding is different from printing. A tag can have a printed serial number, QR code, or barcode without having the corresponding RFID memory encoded.
2. Do All RFID Tags Need to Be Pre-Encoded?
No.
Whether pre-encoding is necessary depends mainly on how the RFID tags will be used.
Blank RFID Tags
Blank tags are supplied without application-specific data being written into the RFID memory.
They may be suitable when:
The customer has its own RFID encoding equipment
Tags are encoded during production
EPC numbers are generated by the customer's software
The customer wants to control the encoding process internally
The final data is not known when the tags are manufactured
Blank tags can provide more flexibility, particularly for applications where tag information changes during the production or logistics process.
Pre-Encoded RFID Tags
Pre-encoded tags may be preferable when:
Each tag must have a unique identity before shipment
The customer does not have an RFID encoder
Tags need to be matched with printed serial numbers
Tags are going directly into an existing inventory system
The customer wants to reduce encoding work at its facility
The application requires strict traceability
For large-volume projects, pre-encoding can simplify the customer's production workflow, but the encoding requirements should be clearly defined before production begins.
3. What Data Can Be Written to an RFID Tag?
The available memory and writable areas depend on the RFID chip and tag configuration.
For many UHF RFID applications, the EPC memory is the primary area used for application identification. Some chips also provide User Memory for additional application-specific information.
Possible data requirements include:
Unique EPC number
Product identification number
Asset ID
Serial number
Internal item code
Customer-defined identifier
Batch or lot information
Data associated with a printed barcode or QR code
However, not all application data needs to be stored directly on the RFID tag.
A common system architecture is to store a unique identifier such as an EPC on the tag and keep the detailed product information in a database.
For example:
RFID Tag → EPC: 300833B2DDD9014000000001
The backend system can then associate that EPC with:
Product: Industrial Pump A
Serial Number: IP-2026-00001
Production Date: September 2026
Location: Warehouse B
Status: In Stock
This approach can reduce the amount of information that needs to be written to the tag.
4. Should the EPC Be Sequential?
Not necessarily.
Some customers use sequential EPC numbers because they are easy to generate and manage.
For example:
000001
000002
000003
000004
Other systems use structured identifiers containing product codes, company identifiers, serial numbers, or other data.
The appropriate format depends on the customer's inventory or traceability system.
The important point is that the RFID supplier should receive a clearly defined encoding rule rather than simply being told to “encode the tags.”
5. RFID Encoding vs. Printing
One of the most common sources of confusion is assuming that printed information and RFID data are automatically the same.
They are separate processes.
For example, a tag may contain:
Printed:
Serial No.: SN000123
Barcode: 6901234567890
RFID Memory:
EPC: 300833B2DDD9014000000123
These values may be related, but they do not automatically have to be identical.
If the printed number, barcode, and EPC must correspond to each other, this requirement should be clearly specified to the supplier.
A typical requirement might be:
The printed serial number, barcode, and RFID EPC must correspond to the same product record.
This allows the supplier to establish an appropriate printing and encoding workflow.
6. When Should RFID Tags Be Pre-Encoded?
Pre-encoding is particularly useful when the RFID tags are going directly into a controlled production or logistics process.
For example, consider an asset management project.
The customer has 5,000 assets and wants every asset to have a unique RFID identity.
Instead of receiving 5,000 blank tags and encoding them manually, the customer can provide the required data list to the RFID supplier.
The supplier can then:
Import the customer's encoding file
Write the data into the RFID tags
Verify the written data
Print the corresponding information
Perform RFID read verification
Package the tags according to the customer's requirements
This can reduce the amount of manual encoding required after delivery.
7. When Are Blank RFID Tags Better?
Blank tags can be more appropriate when the customer's data is generated dynamically.
For example, a factory may generate a unique serial number only when a product reaches a particular production stage.
In this situation, pre-encoding all tags several weeks before production may not be practical.
The factory can instead:
Apply a blank RFID tag to the product
Generate the product's unique ID
Encode the RFID tag using an on-site RFID printer or encoder
Register the ID in the production system
Continue with the manufacturing process
This provides greater control over the encoding process.
8. What File Should You Send to the RFID Supplier?
If you require pre-encoded RFID tags, the supplier will normally need an encoding data file.
The exact format should be agreed in advance.
A simple example might look like:
No.Printed Serial NumberEPC1SN000001300833B2DDD90140000000012SN000002300833B2DDD90140000000023SN000003300833B2DDD9014000000003
Depending on the project, additional fields may be required, such as:
Product model
Barcode
QR code
Batch number
Customer item number
Internal reference number
The supplier should confirm exactly which fields will be used for RFID encoding and which fields are only for printing or database management.
9. Should RFID Tags Be Locked After Encoding?
This depends on the application.
Some projects require the EPC or other memory areas to remain writable because information may need to be updated later.
Other projects require encoded information to be protected from unauthorized modification.
Certain UHF RFID chips provide password-based access-control functions, but the available functions depend on the specific chip and implementation.
Therefore, buyers should clearly state whether the encoded data should be:
Writable
Permanently locked
Password protected
Verified but left writable
Do not assume that all RFID tags use the same locking mechanism.
10. How Should Pre-Encoded RFID Tags Be Verified?
Pre-encoding should not end when the data is written.
The supplier should also verify that the written data can be read correctly.
A basic verification process can include:
Step 1: Write the required data
The encoding system writes the specified EPC or other data to the tag.
Step 2: Read the tag again
The tag is read using an RFID reader to confirm that the data was successfully written.
Step 3: Compare the result
The actual RFID data should be compared against the customer's original encoding file.
Step 4: Check printed information
If printing is required, the printed serial number or barcode should be checked against the corresponding RFID data.
Step 5: Record failures
Any tags that fail encoding or verification should be identified and separated according to the agreed production procedure.
For large-volume orders, this verification process is particularly important because a small error rate can affect hundreds or thousands of tags.
11. Common Mistakes When Ordering Pre-Encoded RFID Tags
Several problems can be avoided by defining the encoding requirements before production.
Mistake 1: Saying Only “Please Encode the Tags”
This does not tell the supplier what data should be written or how it should be formatted.
Mistake 2: Providing Only a Printed Serial Number
A printed serial number does not automatically define the RFID EPC.
Mistake 3: Not Defining the Starting Number
If sequential EPCs are required, specify the starting value and numbering rule.
Mistake 4: Not Explaining the Relationship Between EPC and Barcode
If the EPC must correspond to a barcode or QR code, this should be clearly stated.
Mistake 5: Changing the Encoding Format After Production Starts
Encoding rules should ideally be finalized before mass production.
Mistake 6: Not Defining Whether Tags Can Be Rewritten
If the customer needs to update the tag later, the supplier should know that the memory must remain writable.
12. What Should You Tell Your RFID Supplier?
Before ordering pre-encoded RFID tags, provide the supplier with the following information:
RFID frequency
RFID chip
Tag model or specification
Required EPC format
Required memory area
Encoding quantity
Encoding data file
Starting number, if applicable
Sequential or non-sequential numbering
Relationship between EPC and barcode/QR code
Printing requirements
Whether data must be verified
Whether memory should remain writable
Whether password protection is required
Packaging requirements
The more clearly these requirements are defined, the less likely it is that encoding errors will occur during mass production.
Pre-Encoding Checklist
Before placing an order, confirm:
Do the tags need to be pre-encoded?
Which memory area needs to be encoded?
What RFID chip is being used?
What is the exact EPC/data format?
Is the numbering sequential?
What is the starting number?
Does the EPC need to correspond to a barcode or QR code?
Will the supplier provide encoding verification?
Should the data remain writable?
Is password protection required?
Has the encoding data file been finalized?
Conclusion
Whether RFID tags should be pre-encoded depends on the application's production workflow, data management requirements, and available encoding equipment. Pre-encoded tags can simplify deployment when each tag needs a predefined identity, while blank tags can provide greater flexibility when data is generated during production.
The key is to define the encoding requirements before mass production. EPC format, numbering rules, printed information, verification procedures, and memory protection should all be agreed with the RFID supplier in advance.
For customized RFID tags, China Smart Card can support different tag constructions, printing, encoding, and application-specific requirements. Contact us with your application details and encoding requirements to discuss a suitable RFID tag solution.
