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The Anatomy of a National Drug Code (NDC)

Aug 31, 2020 | Drug & Biologic Product Submissions, Pharmaceutical and Cosmetics

Per the Drug Listing Act of 1972, part of the Food and Drug Administration (FDA) requirement to electronically list drug products (Rx and OTC) includes the assignment of a National Drug Code (NDC). An NDC is a 10 digit number that uniquely and universally identifies a drug product by stringing together three separate code segments with hyphens. Asterisks were once used to indicate certain configurations of the NDC, but this is no longer the case. A complete NDC is made up of a labeler code, a product code and package code segment, with dashes between each segment. The NDC Directory does not contain all listed drugs, but will contain all over-the-counter (OTC) medications, prescription medications, and insulin packages in the U.S.A. Animal drugs, blood products, and human drugs not in final marketed form will not be included in the directory. However, having an NDC does not equate to approval from the FDA.

Code Configurations

NDCs are configured in either 5-3-2 or 5-4-1 formats. While 5-3-2 is the most common format selected by labelers, some companies with large product portfolios find that 5-4-1 works better for them, since it allows for ten times the number of product codes as 5-3-2. 5-4-1 does, however, limit the number of available package codes per product to ten (0-9).

It is important to note that a labeler must select and stick with one or the other of these formats. FDA does not allow switching back and forth between 5-3-2 and 5-4-1 based on what is convenient for each product. Labelers should consider carefully not only their current product portfolios and packaging configurations but also any plans for future product offerings when selecting a format.

First Segment – The Labeler Code

The NDC Labeler Code makes up the first segment of the complete NDC. A Labeler Code is five digits (with some exceptions for earlier codes, which may be only four) and identifies the company responsible for distributing the product in the United States. The Labeler Code is the only portion of the NDC which is assigned by the FDA. The remaining portions are assigned by the labeler company and then registered with FDA through the electronic drug listing process. This allows labelers to choose between the 5-3-2 and the 5-4-1 set up. To obtain a labeler code, you must submit an electronic NDC Labeler Code Request to the FDA.

In our fictitious NDC example above, the labeler code is 12345. The code would have a labeler name associated with it in the FDA’s database—Acme Medicine Co., for instance. Once a labeler code is assigned by the FDA, all products from that labeler will begin with the same code. For instance, all Acme product NDCs would begin with labeler code 12345.

Second Segment – The Product Code

The product code segment identifies the specific product in question. For example, a 200mg coated ibuprofen tablet from the same labeler would be identified by the same product code in all of its packaging configurations. So, in the example above, NDC 12345-123 could signify a 200mg coated ibuprofen tablet distributed by Acme Medicine. If Acme had a variation of this product with a different attribute (e.g., a 200mg ibuprofen liquid capsule), it would receive a separate product code (e.g., 12345-124).

Third Segment – The Package Code

The final segment of an NDC is the package code. The package code identifies in what configuration the product is offered for sale. For instance, NDC 12345-123-01 may identify Acme’s 200mg, film-coated ibuprofen tablet, distributed in a bottle of 25 tablets. NDC 12345-123-02 may signify a bottle of 100 of the same tablets.

When registered, each NDC code represents the product and is linked to all applicable information in the NDC directory. This information includes proprietary name, non-proprietary (generic) name, dosage, route of administration, and type of product, such as OTC or prescription.

Billing Conversion – The 11 Digit Code

Proper billing of an National Drug Code requires an 11 digit NDC, in the format of 5-4-2, instead of the 10 digit NDC printed on labels. The 10 digit code can easily be converted to an 11 digit code with special placement of a ‘0’ at the beginning of whichever segment in the 10 digit number is not long enough for the 5-4-2 format. Looking at our earlier example, NDC 12345-123-01 may identify Acme’s 200mg, film-coated ibuprofen tablet, distributed in a bottle of 25 tablets, but it will need to be converted to 11 digits for billing. To make this conversion we can look at the current number, in its 5-3-2 format, and check where a zero would change the format to 5-4-2. In this case, the middle segment will be affected, changing the billing code to NDC 12345-0123-01. This 11 digit number can also be used by various government agencies or private players for purposes other than billing.


Important as they are, NDCs are just a small component of FDA’s electronic drug listing process. The information above is only the basics, and you may have many questions about assigning NDCs to your drug products , electronically listing them, and updating drug listed data. Reed Tech has been helping drug product labelers and manufacturers from the earliest days of electronic drug listing. Feel free to contact us and one of our experts will be glad to help.