The NDC number explained, from 10 digits to 12

On March 5, 2026, FDA published a final rule¹ that will make every National Drug Code 12 digits long. The change takes effect March 7, 2033, and will touch every drug label, barcode and pharmacy claim in the country. The reason is arithmetic. The five-digit codes that identify drug companies allow 90,000 possibilities, and FDA expects to run out in about 10 to 15 years at the current pace of assignment.

Drug products listed with FDA carry an NDC as their product identifier. It is printed on stock bottles and cartons, encoded in barcodes, and required in electronic pharmacy claims. Price benchmarks, recall notices and drug databases all use it to pin down a specific product and package, including the federal NADAC price files behind GxRadar's price pages.

A code that looks simple already comes in three 10-digit formats, gets reshaped to 11 digits for billing, and is now headed for a third length.

Three segments, three jobs

According to FDA's NDC background page², each listed drug product gets a unique 10-digit, three-segment number.

So a 30-count bottle and a 90-count bottle of the same tablet share the first two segments and differ in the third. The same drug and strength from two different manufacturers differ in the first segment, which is one reason a refill can look different, as GxRadar's piece on why your pill changed color explains. A repackager that buys a product in bulk and puts it into new containers lists it under its own labeler code.

Why there are three 10-digit formats

Segment lengths are not fixed. A 10-digit NDC can be split 4-4-2, 5-3-2 or 5-4-1, as FDA explains². Older firms hold four-digit labeler codes, which leaves six digits for product and package. FDA now assigns only five-digit labeler codes, so the firm chooses between a three-digit product code with a two-digit package code or a four-digit product code with a one-digit package code.

Because the split varies, the hyphens carry information. Without them, there is no reliable way to tell where one segment ends and the next begins.

Eleven digits for billing

When HHS adopted standards for electronic health care transactions under HIPAA, in a final rule published Aug. 17, 2000⁵, it named the NDC as the standard code set for drugs and adopted a uniform 11-digit format. That format is always 5-4-2. To convert, a leading zero is added to whichever segment is short.

FDA uses the middle example in its rulemaking¹. The other two are illustrative digit patterns that do not belong to real products.

FDA's own listing system uses the 10-digit form; the 11-digit version is a conversion. Pharmacy claims and many government drug datasets, including the NADAC price files described in how NADAC is calculated, use the 11-digit form, often without hyphens. The 2026 rule¹ prints the conversion side by side with the native formats, which is where the trouble described below begins.

How to look up an NDC

FDA publishes listed NDCs in the National Drug Code Directory³, which is updated daily. It covers active, certified finished and unfinished drugs submitted in electronic listing files. Finished drugs include prescription and over-the-counter products, approved and unapproved drugs, and repackaged and relabeled drugs.

1. Open the NDC Directory search on FDA's website.
2. Enter the NDC with hyphens if you have them. With only an 11-digit billing code, remove the padding zero from the short segment to recover the 10-digit form; if the format is unknown, try each possible split.
3. Check the result's labeler, proprietary and nonproprietary names, strength, dosage form, package description and marketing start date.
4. For bulk use, download the directory files or query the NDC endpoint on open.fda.gov⁴.

The NDC also leads to a product's full labeling, as our guide to looking up a drug on DailyMed shows.

A few limits apply. It shows only listings whose marketing start date has passed and whose marketing end date has not, so a discontinued product can drop out. Animal drugs, blood products, drugs manufactured under contract, and drugs marketed only as part of a kit are excluded from the main directory and published in a separate excluded-drugs file. FDA's directory page³ also states that inclusion does not mean the agency has verified the information, that the labeler is responsible for each entry, and that an NDC does not denote FDA approval or insurance coverage.

Recall notices identify affected products by NDC and lot number, a process covered in how to read an FDA recall notice. The labels patients take home are a separate document, explained in how to read a prescription label.

Why 11 native digits would have collided

FDA had planned for the labeler pool to run out. In a 2016 registration and listing rule⁶ (the system explained in our piece on establishment registration), it wrote that it "will begin issuing 6-digit labeler codes, leading to 11-digit NDCs, only when the available 5-digit labeler codes are exhausted," allowing two new formats, 6-3-2 and 6-4-1, for five in total.

Those native 11-digit codes would have clashed with the converted 11-digit billing codes. In FDA's own example in the 2026 rule¹, the native code 100100-001-01 and the billing code 10010-0001-01 become the same string, 10010000101, once the hyphens are removed. An FDA presentation in September 2023⁹ laid out the same problem.

FDA held a public hearing on Nov. 5, 2018⁷, published a proposed rule for a uniform 12-digit format⁸ on July 25, 2022, and issued the final rule on March 5, 2026.

What the 12-digit rule does

Under the final rule¹, every NDC will be 12 digits in a single 6-4-2 format, with a six-digit labeler code, a four-digit product code and a two-digit package code. Existing NDCs convert by adding leading zeros to the labeler, product or package segment as needed. FDA calls the conversion "a ministerial, administrative change and not the assignment of a 'new' NDC." The agency plans to publish a database mapping each 10-digit NDC to its 12-digit equivalent, at least through the transition, and when the five-digit pool runs out, new six-digit labeler codes will start at 100000, since codes with leading zeros will not be issued.

Barcodes change too. The UPC-A barcode used on many packages cannot hold a 12-digit NDC, so the rule allows linear or 2D barcodes that meet recognized international standards. A GS1 application identifier lets the NDC be encoded in GS1-128, GS1 DataBar and GS1 DataMatrix symbols, which require camera-based scanners. FDA rejected adding letters to labeler codes because letters raise the risk of misreading. The 2D codes overlap with the serialization requirements described in GxRadar's DSCSA explainer.

For three years after March 7, 2033, FDA does not intend to object to 10-digit NDCs on labels already in commerce, according to the rule¹. Little changes for patients before then, and the product behind a converted NDC stays the same. People who work with drug data, in pharmacies, payers, health systems or databases, will need systems that store 12 digits, keep leading zeros and map old codes to new ones. Commenters on the rule flagged one specific hazard. Systems that store the code as a numeric field drop leading zeros, and a 12-digit NDC built by adding leading zeros does not survive that.