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DUNS Number

General

Data Universal Numbering System Number

A unique 9-digit identifier assigned by Dun & Bradstreet to businesses worldwide, widely required for US federal contracting and international trade credit checks.

Definition

A DUNS Number (Data Universal Numbering System Number) is a unique 9-digit identifier assigned by Dun & Bradstreet to individual business entities worldwide. Introduced in 1963, it predates most modern digital identifiers and became a global standard for identifying and tracking businesses for credit reporting, supply chain verification, and — until 2022 — US federal contracting eligibility.

Each physical business location can be assigned its own DUNS Number, meaning a large corporation with multiple offices or subsidiaries may hold several distinct numbers across its structure.

Formula

A DUNS Number has no public checksum algorithm — it is a plain 9-digit sequential identifier assigned internally by Dun & Bradstreet's registration system, not derived from a formula applied to the business's name or details. Structural validation is limited to confirming:

  1. The number is exactly 9 digits.
  2. It contains digits only, with no letters or symbols.

Because there is no mathematical check digit, structural validation only confirms format, not that a number is actually registered — that confirmation requires querying Dun & Bradstreet's own database, which validator tools don't have direct access to.

Worked Example

A structurally valid but entirely fictional example: 123456789, displayed as a plain 9-digit string with no separators.

Key Things to Know

  • No checksum, unlike Aadhaar: DUNS Numbers can only be format-checked (9 digits, numeric only) via the DUNS Validator — actual registration must be confirmed with Dun & Bradstreet directly, unlike the built-in checksums used by Aadhaar or CUSIP.
  • Required for many trade relationships: large enterprises and international trade credit checks often require a DUNS Number even outside federal contracting.
  • Replaced by UEI for US federal contracts: since April 2022, US federal contractors register with a Unique Entity ID (UEI) via SAM.gov instead of a DUNS Number, though DUNS remains active for private-sector credit checks.
  • Free to obtain: Dun & Bradstreet issues DUNS Numbers at no charge, though paid expedited processing is available.
  • One per business location: multi-location businesses often hold multiple DUNS Numbers, one per physical site or subsidiary.
  • Distinct from EIN: an EIN is a US federal tax ID; a DUNS Number is a private, global business credit identifier — the two serve entirely different purposes.

Related Terms

EINUS Employer Identification NumberGTINGlobal Trade Item Number

Frequently Asked Questions

No, a DUNS Number has no public checksum formula — it is a 9-digit sequential identifier assigned and maintained privately by Dun & Bradstreet, not derived from a mathematical algorithm. Validation is limited to checking the correct length and digit-only format with a tool like the [DUNS Validator](/validators/duns-validator/); confirming that a number is actually registered requires querying Dun & Bradstreet's database.
A DUNS Number is required to register for US federal government contracts through the System for Award Management (SAM), and is also widely used internationally as a trade credit reference when businesses evaluate the creditworthiness of a potential partner or supplier. Many large corporations also require vendors to provide a DUNS Number as part of onboarding.
No. An [EIN](/glossary/ein/) is a US federal tax identifier issued by the IRS, while a DUNS Number is a global business identifier issued by the private company Dun & Bradstreet for credit reporting and contracting purposes. A single business typically holds both, used in different contexts.
Yes, businesses can request a DUNS Number from Dun & Bradstreet at no cost, though the process can take several days to a few weeks depending on verification requirements. Expedited paid processing is also offered by Dun & Bradstreet for businesses that need a number issued faster.
The US federal government transitioned from DUNS Numbers to the Unique Entity ID (UEI) generated directly within SAM.gov as of April 2022, but DUNS Numbers remain in active use internationally for trade credit and vendor verification outside of federal contracting. Businesses working with both US federal agencies and international partners may need to track both identifiers.