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Federal Contracting · Fonteum Data GlossaryRegulatory

DUNS vs UEI: what changed?

DUNS was the older nine-digit Dun & Bradstreet identifier used in federal award systems; UEI is the 12-character identifier now generated by SAM.gov. Since April 4, 2022, GSA systems use UEI as the authoritative government entity key, while legacy DUNS values remain historical crosswalk data.

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Full name: DUNS Number Compared with Unique Entity Identifier

Short explanation

The DUNS number was a proprietary Dun & Bradstreet identifier that federal systems historically used to identify organizations. The Unique Entity Identifier (UEI) is the government-generated replacement issued in SAM.gov. GSA switched SAM.gov and other systems to UEI on April 4, 2022, so current federal registrations, awards, and exclusions should be read against UEI first, with DUNS retained only for older records and crosswalks.

Related tool: UEI lookup

Last updated: 2026-07-11Reviewed by: Fonteum data standards desk — Source-provenance editorial review. Definitions checked against primary federal sources.

How it’s used

  • SAM.gov registration: new and renewed federal entity registrations now carry a UEI generated by SAM.gov, not a newly issued DUNS number.
  • Award and assistance systems: federal award records use UEI as the current organization key after the April 4, 2022 transition.
  • Historical joins: older datasets may still carry DUNS, so entity-resolution systems keep DUNS as a legacy alias when a safe crosswalk exists.

Frequently asked questions

Is DUNS still used for SAM.gov registration?
No. SAM.gov and other GSA systems switched to the government-generated Unique Entity ID on April 4, 2022.
How many characters are in a UEI?
A UEI is a 12-character alphanumeric identifier generated through SAM.gov for an organization or entity record.
Why do older federal records still show DUNS?
Older award and registration data may retain DUNS because it was the prior entity key. Current systems should use UEI, with DUNS treated as legacy alias data.

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Platform snapshot · 2026-08-12

13.4Mproviders & companiesProviders, organizations, owners, and facilities on file
26.2Msource-linked factsSource-linked field facts in the dated platform snapshot
90sources with dataDistinct snapshot source IDs with at least one positive record count
73fresh sourcesDistinct source IDs whose latest positive-data snapshot falls within the preceding 45 days
111sources integratedActive registry rows; integration does not establish a load
13state Medicaid jurisdictionsDistinct states represented in the state-exclusions serving table

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