National Stock Number (NSN)

A National Stock Number (NSN) is a 13-digit code that uniquely identifies standardized material items of supply used by the U.S. government. It enables consistent identification, procurement, storage, and distribution of items across federal agencies and the military, ensuring that buyers, suppliers, and logistics teams are referring to the exact same item.

What Is a National Stock Number (NSN)?

A National Stock Number (NSN) is a 13-digit code that uniquely identifies standardized material items of supply used by the U.S. government.

It enables consistent identification, procurement, storage, and distribution of items across federal agencies and the military.

NSNs ensure that buyers, suppliers, and logistics teams are referring to the exact same item, eliminating ambiguity in government purchasing and reducing procurement errors.

Key Characteristics of an NSN

13-digit numeric identifier assigned to approved supply items

Structured as a Federal Supply Class (first four digits) and a National Item Identification Number (remaining nine digits)

Used across the Department of Defense and civilian agencies

Managed through a centralized federal logistics system

Supports standardized cataloging and global supply chain tracking

The NSN appears during item cataloging, solicitation, contract award, ordering, invoicing, and inventory management. It is commonly listed in solicitations, purchase orders, and contract line items.

For example, an NSN such as 5305-00-935-5867 identifies a specific type of screw. The first four digits represent the Federal Supply Class, and the remaining digits form the National Item Identification Number that uniquely identifies the item in the federal cataloging system. Contractors must reference the correct NSN when responding to solicitations or fulfilling delivery orders.

Regulatory Framework

NSNs operate within the federal logistics and acquisition framework, including:

Federal Acquisition Regulation (FAR) for procurement requirements

Defense cataloging and logistics policies

Department of Defense supply chain management procedures

Use of NSNs is mandatory when specified in solicitations or contracts involving standardized supply items.

Why NSNs Matter for Contractors

Accurate NSN usage improves eligibility for federal supply contracts and increases visibility in government procurement systems. Manufacturers can request assignment of an NSN for their products, allowing items to be stocked and ordered through federal systems. Key risks include:

Incorrect item identification can result in rejected shipments, payment delays, or contract performance issues

Supplying the wrong item under an NSN may create contractual liability and reputational risk

Common Misconceptions About NSNs

NSNs are only for military items.

Civilian federal agencies also use NSNs for standardized supply items.

An NSN is the same as a manufacturer part number.

A part number is manufacturer-specific, while an NSN is government-standardized and may apply across multiple manufacturers.

Each product variation shares one NSN.

Each distinct item configuration receives its own unique NSN.

Frequently Asked Questions

What does the 13-digit NSN represent?

The first four digits identify the Federal Supply Class. The remaining nine digits form the National Item Identification Number, which uniquely identifies the item.

Who assigns National Stock Numbers?

NSNs are assigned through the federal cataloging system managed by defense logistics authorities.

Can a commercial item have an NSN?

Yes. Commercial products can receive an NSN if they are approved for government use and cataloged accordingly.

Is an NSN required to sell to the government?

Not always. NSNs are required when a solicitation specifies them or when supplying standardized items within the federal supply system.