Understanding What is the 11-Digit Drug Code (NDC)

October 11, 2025 •

4 min read

Over 90% of prescription drugs and over-the-counter medications sold in the United States carry a unique National Drug Code (NDC), a standard identifier that is often converted into an 11-digit drug code for administrative purposes like billing and claims processing. This numerical code serves as a universal product identifier for human drugs.

Quick Summary

The National Drug Code (NDC) is a unique, three-segment number used to identify human drugs in the U.S. While often displayed as 10 digits on packaging, it must be converted to an 11-digit, 5-4-2 format for healthcare billing and electronic claim submission. The code identifies the drug's manufacturer, specific product characteristics, and package size.

Key Points

NDC Definition: The National Drug Code (NDC) is a three-segment, unique identifier for all human drugs in the U.S..
10-to-11-Digit Conversion: While NDCs can appear as 10 digits on packaging, they are converted to an 11-digit, 5-4-2 format for billing by adding a leading zero.
Code Segments: The 11-digit code consists of a 5-digit labeler code, a 4-digit product code, and a 2-digit package code.
Billing Standardization: The 11-digit NDC standard was implemented to comply with HIPAA and to ensure accurate electronic claims processing across healthcare systems.
Identification Purpose: The code provides specific details about a medication, including the manufacturer, dosage form, strength, and package size, which aids in inventory management and patient safety.
Zero Placement: The location of the added leading zero for conversion depends on which of the 10-digit NDC's segments is too short.

What is the 11-Digit Drug Code and How It's Formed?

The National Drug Code (NDC) is the unique, universal product identifier for all human drugs marketed in the United States, as mandated by the U.S. Food and Drug Administration (FDA). This code, which appears on all prescription and non-prescription medication packaging, consists of three distinct segments. While the code on the label is often 10 digits long, administrative standards, such as those governed by the Health Insurance Portability and Accountability Act (HIPAA), require it to be presented as an 11-digit drug code in a standardized 5-4-2 format. This conversion is critical for accurate billing and claims processing.

The Three Segments of an NDC

The three parts of the National Drug Code each represent specific information about the drug. Understanding these segments is key to deciphering the full identifier.

Labeler Code (First 5 digits): This segment identifies the manufacturer, repackager, or distributor of the drug. The FDA assigns this portion of the code.
Product Code (Next 4 digits): This code identifies the specific strength, dosage form (e.g., tablet, liquid, capsule), and formulation of the drug for that particular labeler.
Package Code (Last 2 digits): This segment identifies the specific package size and type (e.g., bottle of 100 tablets, vial, tube).

The most significant source of confusion surrounding the NDC is the variation in its length. A 10-digit code printed on a package must be converted to an 11-digit code for billing purposes by strategically adding a leading zero. The placement of this zero depends on which of the three segments is shorter than its required length for the 5-4-2 format.

The Conversion from 10 to 11 Digits

The need to convert a 10-digit NDC to an 11-digit version arises because original 10-digit codes on drug labels can appear in three different formats: 4-4-2, 5-3-2, and 5-4-1. This variability can cause issues in automated systems. To create a uniform standard for electronic health records (EHRs) and billing claims, a single 5-4-2 format is required, which necessitates adding a leading zero to the segment that is short by one digit.

Example 1: 4-4-2 Format to 5-4-2: An NDC like 1234-5678-90 becomes 01234-5678-90 by adding a leading zero to the labeler code segment.
Example 2: 5-3-2 Format to 5-4-2: An NDC like 12345-678-90 becomes 12345-0678-90 by adding a leading zero to the product code segment.
Example 3: 5-4-1 Format to 5-4-2: An NDC like 12345-6789-0 becomes 12345-6789-00 by adding a leading zero to the package code segment.

The conversion is a critical administrative step performed by healthcare providers, pharmacists, and billing personnel. Its purpose is to ensure that the correct drug, dosage, and package size are accurately documented and billed, which helps prevent errors and streamlines the claims process.

Importance of the 11-Digit Standard

Using a standardized 11-digit NDC is vital for several reasons:

Claims Processing: It provides a uniform format for payers and clearinghouses to process claims accurately, reducing errors and delays in reimbursement.
Patient Safety: Accurate identification of medications is crucial for tracking and for reducing the risk of medication errors. The NDC helps distinguish between different formulations and strengths of the same drug.
Data Consistency: Standardizing the NDC format helps maintain consistency across different healthcare systems, including EHRs, pharmacy databases, and administrative software.
Supply Chain Management: It enables better tracking of drugs through the entire supply chain, from manufacturer to patient, for purposes of recalls, distribution, and inventory management.

Challenges with NDC Formatting

Despite the clear benefits of the 11-digit standard, challenges persist. Some systems may still use or display 10-digit codes, which can lead to ambiguity during conversion if the original 10-digit format is unknown. This was the primary driver for the standardization initiative. The FDA has also considered moving to a uniform 12-digit format in the future to resolve these ambiguities, though this change has not yet been implemented.

NDC Format Comparison: 10 vs. 11 Digits

To visualize the difference, the table below shows how a 10-digit NDC, as it might appear on a product label, is converted to the standardized 11-digit format required for billing.


10-Digit (on Label) Format	10-Digit Example	11-Digit (for Billing) Format	11-Digit Conversion	Location of Added '0'
4-4-2	`1234-5678-90`	5-4-2	`01234-5678-90`	Beginning of the Labeler Code
5-3-2	`12345-678-90`	5-4-2	`12345-0678-90`	Beginning of the Product Code
5-4-1	`12345-6789-0`	5-4-2	`12345-6789-00`	Beginning of the Package Code

Conclusion

Understanding what is the 11-digit drug code is essential for anyone involved in the healthcare ecosystem, from pharmacists and physicians to billing specialists and patients. It is not just a longer number but a standardized representation of the National Drug Code (NDC), formatted specifically to eliminate ambiguity and facilitate accurate electronic claims processing. The 11-digit format, based on the 5-4-2 segment structure, ensures that the unique identifiers for a drug's manufacturer, product, and package size are consistently reported across the industry, contributing significantly to both administrative efficiency and patient safety. For those seeking detailed information on specific NDCs, the FDA publishes a directory of all listed NDCs.

Frequently Asked Questions

The 10-digit NDC is often the number printed on a drug's packaging, while the 11-digit NDC is the standardized format used for electronic claims processing and billing, achieved by adding a leading zero.

Using the 11-digit, 5-4-2 format for billing eliminates ambiguity that can arise from 10-digit NDCs with variable segment lengths. This standardization helps ensure accurate claims processing and prevents delays in reimbursement.

The leading zero is added to the segment that is one digit shorter than its standardized length. For example, a 4-digit labeler code gets a leading zero to become 5 digits.

The FDA assigns the first segment, the labeler code. The manufacturer or labeler then assigns the remaining two segments—the product code and the package code.

No, inclusion in the NDC Directory and having a code does not mean a drug has FDA approval. It is simply a product identifier for drugs marketed in the US.

Submitting a 10-digit NDC or an improperly formatted 11-digit code can cause claim rejections, payment delays, and administrative complications.

While the NDC is the universal identifier for human drugs in the U.S., other coding systems like HCPCS and CPT codes are also used in billing for drug-related services.