NDC (National Drug Code)

An NDC identifies a specific drug product at a specific package size, not just a drug by name. It's built from three segments:

• Labeler code — assigned by FDA to the company that manufactures, repacks, or distributes the product under its own name.
• Product code — identifies the specific strength, dosage form, and formulation.
• Package code — identifies the package size and type (a bottle of 30 tablets vs. a bottle of 100 is a different package code on the same product).

The current format is 10 digits total, split across the three segments as 4-4-2, 5-3-2, or 5-4-1 depending on how many digits FDA assigned to that labeler's code. The NDC appears on the drug's label and in FDA's public NDC Directory, and it's the key healthcare distributors and PIMs use to anchor everything else about that product — strength, form, pack size, NDC status.

An NDC and a GTIN serve different registries and don't automatically interoperate. The NDC is assigned by FDA as part of drug registration; a GTIN or UPC is assigned by the manufacturer under a GS1 company prefix, independent of FDA.

For retail OTC products, the two usually coexist: the 10-digit NDC is converted to an 11-digit numeric string by zero-padding whichever segment is shorter than its standard length, and that 11-digit NDC is embedded inside a 12-digit UPC-A barcode (with a leading '3' and a check digit) so the product scans at retail. A distributor or pharmacy system that only stores the barcode's UPC, without also capturing the underlying NDC segments, loses the ability to match that product against FDA recall data or NDC Directory listings — which is why product data operations for healthcare distributors typically maintain an explicit NDC-to-GTIN cross-reference rather than treating the two as interchangeable.

FDA finalized a rule on March 5, 2026 adopting a 12-digit NDC format — a 6-digit labeler code, a 4-digit product code, and a 2-digit package code (6-4-2) — to replace the current 10-digit scheme once the supply of available 10-digit labeler codes runs out. The rule takes effect March 7, 2033.

Existing NDCs convert by zero-padding each segment up to the new segment length, so a 10-digit NDC and its 12-digit successor represent the same product; FDA treats them as the same NDC in two formats, not two different identifiers. Until the effective date, the 10-digit format remains standard, but any product data pipeline that stores NDC as a fixed-length string rather than as three distinct, padded segments will need to handle both lengths through the transition.

Treating an NDC as a flat 10- or 11-digit string, rather than as three semantically distinct segments, is where most downstream matching breaks: a labeler code reused across hundreds of SKUs, a product code that changes when a formulation changes but the brand name doesn't, and a package code that multiplies one product into a dozen catalog records. Healthcare distributors and manufacturers enriching catalog data need the NDC captured as its own attribute — separate from GTIN — normalized to a consistent segment format, and cross-referenced to the GTIN or UPC used on the retail or GDSN side, so that a recall, a repack, or the 2033 format change doesn't silently break the match between a catalog record and the regulatory identifier it's actually describing.