The three parts of a National Drug Code (NDC) number identify who made the drug, which specific drug it is, and how it’s packaged. Every prescription and over-the-counter medication sold in the United States carries this unique 10-digit code, split into three segments separated by hyphens.
The Three Segments at a Glance
An NDC like 0777-3105-02 breaks down into three distinct pieces of information:
- First segment (labeler code): Identifies the company that manufactures, distributes, or relabels the drug. The FDA assigns this number directly.
- Second segment (product code): Identifies the specific drug product, including its strength, dosage form, and formulation. The company proposes this number.
- Third segment (package code): Identifies the package size and type, distinguishing between different containers of the same drug.
Together, these three segments pinpoint not just a medication, but the exact version in the exact container from the exact company.
Labeler Code: Who Made or Distributes It
The first set of digits is the labeler code, and it’s the only segment assigned directly by the FDA. A “labeler” isn’t always the manufacturer. It can be any firm that manufactures, repacks, or distributes a drug product under its own name. So if a pharmacy chain sells a generic ibuprofen under its store brand, that chain has its own labeler code, separate from the company that physically made the tablets.
The labeler code is either four or five digits long, depending on when the company registered with the FDA and how many codes were available at the time.
Product Code: Which Drug and What Strength
The second segment narrows things down to the specific product. It captures three characteristics: the drug’s strength (like 200 mg vs. 400 mg), its dosage form (tablet, capsule, liquid, cream), and its formulation. Two products from the same company that differ in any of these ways will have different product codes.
The labeler proposes this number rather than receiving it from the FDA. It’s either three or four digits long, depending on the format of the overall NDC.
Package Code: What Container It Comes In
The third segment differentiates between packaging options. The same 500 mg acetaminophen tablet from the same manufacturer might come in a bottle of 50, a bottle of 100, or a blister pack of 30. Each of those gets a unique package code, which is one or two digits long. It captures both the quantity and the type of container.
Why the Digit Count Varies
The full NDC is always 10 digits, but the three segments can be split in different ways. There are three valid configurations:
- 4-4-2: 4-digit labeler code, 4-digit product code, 2-digit package code
- 5-3-2: 5-digit labeler code, 3-digit product code, 2-digit package code
- 5-4-1: 5-digit labeler code, 4-digit product code, 1-digit package code
The hyphens in the NDC tell you which format you’re looking at. Without them, you wouldn’t know where one segment ends and the next begins.
The 11-Digit Version Used in Billing
If you’ve seen NDCs on insurance claims or pharmacy receipts, you may have noticed they’re 11 digits instead of 10. HIPAA requires a standardized 11-digit format (5-4-2) for electronic billing and reimbursement. To convert, a leading zero is added to whichever segment is shorter than the standard length. A 4-4-2 NDC gets a zero added to the front of the labeler code. A 5-3-2 gets a zero added to the front of the product code. A 5-4-1 gets a zero added to the front of the package code.
The underlying information stays the same. The extra zero is purely a formatting tool so that every system reading the number can parse it the same way.
Where to Find the NDC on a Label
The NDC appears on all prescription and over-the-counter medication packages and inserts sold in the United States. On most bottles and vials, it’s printed near the barcode, typically preceded by the letters “NDC.” On blister packs, it’s usually on the outer carton. If you need to look up what an NDC corresponds to, the FDA maintains a National Drug Code Directory that’s updated daily and is searchable online. It covers finished drugs, active pharmaceutical ingredients, and compounded drugs.
The Coming Shift to 12 Digits
The FDA is running out of available 10-digit NDC combinations. In 2022, the agency proposed switching to a uniform 12-digit format with a fixed 6-4-2 structure: six digits for the labeler, four for the product, and two for the package. This would eliminate the confusion of multiple digit configurations and provide a much larger pool of available codes.
If finalized, the new format would take effect five years after the final rule is published, with an additional three-year transition period during which old 10-digit codes could still appear on packaging. During that window, the FDA plans to publish both the old and new NDC for each product to reduce the risk of medication errors.