CAGE Code vs NSN: What's the Difference?

If you've spent any time sourcing aerospace or defense parts, you've bumped into these two terms more than once. They get thrown around together so often that people assume they're interchangeable.

They're not.

A CAGE Code identifies who makes or supplies a part. An NSN identifies what the part actually is. One points to a company, the other points to a specific, standardized item. In real-world procurement, you almost always need both, together, to confirm you're buying the right part from a legitimate, traceable source.

Below, we'll go beyond the basic definitions and cover how these two systems actually work together on a purchase order, where buyers commonly get tripped up, how to verify a part before you commit to it, and why this distinction matters so much in aerospace and defense supply chains specifically.

What Is a CAGE Code?

A CAGE Code (Commercial and Government Entity Code) is a five-character identifier assigned to a specific company, manufacturer, distributor, or government activity. Think of it as a business fingerprint: no two organizations share the same one.

It's issued and maintained by the Defense Logistics Agency (DLA) in the U.S. Outside the U.S. and Canada, NATO member and sponsored nations use the equivalent NCAGE code, and both systems are cross-referenced through the NATO Codification System (NCS) so a part's supplier can be identified globally. CAGE Code directories compile these identifiers alongside their associated organizations, making it easier to reference manufacturers and suppliers across the aerospace and defense industries.

A CAGE Code tells you:

• Who the manufacturer, distributor, or supplier is
• Where that business is physically located
• Whether the entity is active, registered, and eligible for government contracting
• In some cases, whether the entity is the original manufacturer or an approved distributor

What Is an NSN?

An NSN (National Stock Number, also called a NATO Stock Number) is a 13-digit code that identifies a specific, standardized item, down to the exact part, regardless of who manufactures it.

Unlike a CAGE Code, an NSN has nothing to do with who made the part. It's purely about what the item is. Two, five, or twenty different manufacturers can produce the identical, form-fit-function part, and it'll carry the same NSN either way.

An NSN breaks down into two main components:

An NSN (National Stock Number) consists of two primary segments: the Federal Supply Classification (FSC) and the National Item Identification Number (NIIN). The FSC is the first four digits of the NSN and identifies the item's general category, such as bearings, fasteners, or avionics components. The NIIN makes up the remaining nine digits and uniquely identifies a specific item. It begins with a 2-digit National Codification Bureau (NCB) code, which indicates the country that assigned the number, followed by a 7-digit item identifier that distinguishes the item from all others within the system.

The NIIN is technically the "unique" part of the number, meaning it's what stays constant even if the FSC classification is ever revised. This distinction trips up a lot of buyers who assume the entire 13-digit string is arbitrary; it isn't, and knowing the structure helps when you're cross-referencing parts manually.

Sourcing teams that work with catalogued military and aerospace hardware rely on NSNs constantly to find exact-match, interchangeable parts. If you're not familiar with how the numbering system works or how to search a live catalog by NSN, this breakdown of NSN parts is a solid place to start.

CAGE Code vs NSN: Side-by-Side Comparison

lthough CAGE Codes and NSNs are often used together, they identify different things and serve different purposes.

What They Identify

A CAGE Code identifies a specific company or supplier, while an NSN identifies a standardized part or item.

Format

A CAGE Code contains five alphanumeric characters. An NSN consists of 13 digits, including a 4-digit Federal Supply Classification (FSC) and a 9-digit National Item Identification Number (NIIN).

Purpose

CAGE Codes are used to verify supplier identity and government contracting eligibility. NSNs are used to identify, catalog, and procure exact, interchangeable parts.

Supplier vs. Part

Each CAGE Code belongs to one organization, whereas a single NSN can be associated with the same item supplied by multiple approved manufacturers.

Where They're Found

CAGE Codes appear on SAM.gov, government contracts, and supplier documentation. NSNs are commonly listed in DLA FLIS, technical manuals, and parts catalogs.

The simplest way to remember it: CAGE Code = who. NSN = what.

How CAGE Codes and NSNs Work Together in Real Procurement

This is the part most articles skip, and it's the part that actually matters when you're placing a purchase order.

Here's what a typical sourcing workflow looks like:

• You identify the part you need, usually via drawing number, part number, or existing NSN from a maintenance manual or illustrated parts catalog (IPC).
• You look up the NSN to confirm it's the correct, current, standardized item, and to see if it's active, obsolete, or superseded by a newer NSN.
• You pull the list of CAGE Codes associated with that NSN. This is critical: the DLA's cataloging data links every approved manufacturer's CAGE Code to the NSNs of parts they're qualified to produce.
• You select a supplier based on which CAGE Code(s) you trust, have worked with before, or that match the original equipment manufacturer (OEM) or an approved PMA (Parts Manufacturer Approval) source.
• You verify traceability documentation, such as certificates of conformance, material certs, or 8130-3 tags, ties back to that specific CAGE Code.

In other words: the NSN narrows down what you're buying, and the CAGE Code narrows down who you're comfortable buying it from. Skipping either step is how buyers end up with parts that technically "match" on paper but can't be traced back to an accountable source.

If you already know the part number or NSN you need, you can submit an instant RFQ and have a sourcing team cross-reference both the NSN and CAGE Code for you before quoting.

How to Verify a Part Using Both Identifiers

Verification is where CAGE Codes and NSNs earn their keep. Here's a practical checklist:

• Confirm the NSN is current: Search DLA's Federal Logistics Information System (FLIS) or a distributor's catalog to confirm the NSN is active and matches the part's technical specification, not just the part number on a quote.
• Pull the approved manufacturer list for that NSN: This shows every CAGE Code authorized to supply that specific item.
• Verify the supplier's CAGE Code independently: Check it against SAM.gov (the official U.S. government entity registration database) to confirm the business is active, registered, and legitimate.
• Match documentation to the CAGE Code, not just the part: Certificates of conformance, material test reports, and airworthiness tags should reference the same CAGE Code as the approved source, not a third party with no documented link to the manufacturer.
• Flag mismatches immediately: If the CAGE Code on your paperwork doesn't trace back to an approved source for that NSN, treat it as a red flag worth resolving before the order ships.

Distributors that hold AS9120B and ISO 9001:2015 accreditation build this kind of CAGE Code and NSN cross-verification directly into their quality process, since it's part of what those certifications actually audit. You can see how that process is structured on ASAP Aerospace's about page.

Why This Distinction Matters in Aerospace & Defense Supply Chains

Aerospace and defense procurement operates under a much tighter traceability standard than most commercial industries, for good reason: a mismatched or unverified part isn't just a paperwork problem, it's a safety and airworthiness issue.

A few places where the CAGE Code and NSN distinction directly affects outcomes:

• Government contracts and DFARS compliance: Defense contracts frequently require documented traceability back to an approved CAGE Code, not just a matching NSN.
• Obsolete and long-lead-time parts: Older aircraft and legacy defense platforms often rely on parts where the original manufacturer's CAGE Code has changed hands, merged, or gone inactive. Knowing how to trace that history is essential for sourcing hard-to-find parts.
• Counterfeit part prevention: The aerospace industry has dealt with real cases of counterfeit components entering the supply chain carrying legitimate-looking NSNs. Cross-verifying the CAGE Code is one of the primary defenses against this.
• Multi-source procurement: Because a single NSN can map to numerous approved CAGE Codes, buyers often have flexibility to source from multiple qualified manufacturers, which is useful when a preferred supplier has long lead times.

This is also why experienced distributors maintain internal databases that cross-reference part number, NSN, NIIN, CAGE Code, and FSC together. It's not just about finding a match, it's about finding the right, verifiable match.

FAQs

Is a CAGE Code the same as an NSN?

No. A CAGE Code identifies a company or supplier, while an NSN identifies a specific item. They serve different functions and aren't interchangeable, though they're used together during procurement.

Can one NSN have multiple CAGE Codes?

Yes. Since an NSN describes a standardized item, several approved manufacturers can produce that same part, each with its own unique CAGE Code. This is common for aerospace hardware, fasteners, and standard parts.

Do I need both a CAGE Code and an NSN to order aerospace parts?

In most cases, yes. The NSN confirms you're ordering the correct part, and the CAGE Code confirms who's supplying it, which matters for traceability, quality assurance, and government contract compliance.

Who assigns CAGE Codes and NSNs?

In the U.S., the Defense Logistics Agency (DLA) issues both. NATO member and sponsored countries use equivalent systems, NCAGE codes and NATO Stock Numbers, that are cross-referenced internationally through the NATO Codification System.

Does a CAGE Code expire?

CAGE Codes stay active as long as the associated business remains registered and operational. If a company closes, is acquired, or fails to update its registration, the code can become inactive, which is why it's worth verifying current status before relying on older documentation.

What's the difference between an NSN and a NIIN?

An NSN is the full 13-digit number, made up of a 4-digit Federal Supply Classification (FSC) plus a 9-digit NIIN. The NIIN is the portion that stays constant and uniquely identifies the item even if its FSC classification changes.