Federal Supply Classification (FSC) Explained: How the Military Groups Every Part
Federal Supply Classification (FSC) Explained: How the Military Groups Every Part
With millions of distinct items in the federal supply system, the government needs a way to organize them all. That system is the Federal Supply Classification (FSC)—the four-digit code that begins every National Stock Number and tells you, at a glance, what category an item belongs to. For anyone sourcing military parts, the FSC is one of the most practical tools in the catalog.
What Is the Federal Supply Classification?
The FSC is a four-digit number that classifies every cataloged item by what it is. It forms the first four digits of the 13-digit NSN, and it groups items so similar products are cataloged together—screws with screws, valves with valves, avionics with avionics. This is what makes it possible to search and compare across millions of items without drowning in part numbers.
FSG vs. Class: The Two Halves of an FSC
An FSC breaks into two parts: the first two digits are the Federal Supply Group (FSG), a broad category, and the second two digits define the specific class within that group. Using our familiar example:
| Segment | Example | Meaning |
|---|---|---|
| Federal Supply Group (FSG) | 53 | Hardware and Abrasives |
| Class | 05 | Screws |
| Full FSC | 5305 | Screws (within Hardware & Abrasives) |
Examples of Federal Supply Groups
There are dozens of Federal Supply Groups spanning everything the military buys. A few examples show the range:
| FSG | Category |
|---|---|
| 10 | Weapons |
| 15 | Aircraft and Airframe Structural Components |
| 25 | Vehicular Equipment Components |
| 53 | Hardware and Abrasives |
| 59 | Electrical and Electronic Equipment Components |
| 61 | Electric Wire, and Power and Distribution Equipment |
| 66 | Instruments and Laboratory Equipment |
How the FSC Helps You Source
Because the FSC groups items by what they are, it's the fastest way to navigate the catalog. You can scan a list of stock numbers and instantly separate fasteners from electronics from hydraulics, narrow a search to the right class, and find related or alternate items within the same category. For buyers, that classification is the backbone of efficient cross-referencing—a theme we explore in mastering NSN parts procurement.
FSC and the Rest of the NSN
The FSC is only the first four digits. The remaining nine—the National Item Identification Number—pinpoint the exact item. To see how the two work together across the full stock number, read our guide on how to read an NSN, and our breakdown of how FLIS identifies every military part.
Frequently Asked Questions
How many digits is an FSC?
Four—a two-digit Federal Supply Group followed by a two-digit class.
What is the difference between an FSG and an FSC?
The FSG is the broad two-digit group (e.g., 53 = Hardware and Abrasives); the FSC is the full four-digit code that adds the specific class (e.g., 5305 = Screws).
Where does the FSC appear in an NSN?
It's the first four digits of the 13-digit National Stock Number.
Find the Right Part, Faster
Understanding the FSC helps you navigate the catalog; NSN Parts helps you source what's in it. From common hardware to hard-to-find and obsolete components, our team delivers verified, traceable parts across every supply class. Contact us to get started.
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