duns

duns · Recommended

Appears in

Organization

What is it?

A DUNS number (Data Universal Numbering System) is a 9-digit identifier assigned by Dun & Bradstreet to uniquely identify a business entity. Founded in 1844, Dun & Bradstreet maintains one of the largest commercial databases of business information in the world, covering over 500 million companies. A DUNS number is required for US government contracting and grant applications, and is widely used in supply chain and procurement systems globally. Schema.org's duns property lets organizations publish this identifier in structured data.

Why this matters for AEO

Dun & Bradstreet's commercial database is one of the most referenced business data sources in B2B contexts. AI answer engines that draw on business intelligence data can use a DUNS number to pull a company's credit risk profile, corporate family tree, and firmographic data from the D&B registry. For procurement, logistics, and financial AI queries, a DUNS number is a strong entity anchor. Google explicitly recommends duns in its Organization structured data guidelines, though it also notes that iso6523Code with ICD 0060 is the preferred structured format for expressing the same identifier.

What the specs say

Schema.org:duns expects a Text value. The Dun & Bradstreet DUNS number for identifying an organization or business person. [Source: https://schema.org/duns]

Google: Recommended. "The Dun and Bradstreet DUNS number for identifying your Organization." Google's documentation also encourages using iso6523Code as a preferred alternative. [Source: https://developers.google.com/search/docs/appearance/structured-data/organization]

How to find your value

DUNS numbers are assigned and managed by Dun & Bradstreet. To find your company's DUNS:

1. Go to https://www.dnb.com/ and use the D&B D-U-N-S Number lookup tool.
2. Search by your company name and address.
3. If your company already has a DUNS number, it will appear in the results. DUNS numbers are public.
4. If your company does not have one and needs one (e.g., for US government contracting), register at https://www.dnb.com/duns-number.html. Basic registration is free.
5. For US federal contracting, registration through SAM.gov (System for Award Management) also generates or links a DUNS number.

A DUNS number is always exactly 9 digits, with no letters or special characters.

Format and code

DUNS is a plain 9-digit string. Leading zeros must be preserved:

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Microsoft Corporation",
  "duns": "081166849"
}

Microsoft's DUNS number is publicly available through D&B searches. For a company with a leading zero:

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "General Electric Company",
  "duns": "006954321"
}

Invalid formats:

{
  "duns": "08-116-6849"
}

No hyphens or separators belong in the value.

{
  "duns": "D-U-N-S: 081166849"
}

Use only the 9-digit numeric string.

Webflow implementation

Static pages

Add to your homepage or About page via Page Settings > Custom Code > Head Code:

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Your Company",
  "duns": "123456789"
}
</script>

CMS template pages

duns is an organization-level identifier. It does not vary per page or CMS item. Set it once in the site-wide organization schema on your homepage or About page.

In Schema HQ

duns is emitted in the Organization schema editor under the Disambiguation section. Enter your 9-digit DUNS number. Schema HQ validates the field length and publishes it in the organization JSON-LD block across all enabled pages.

Real examples

Dun & Bradstreet is itself registered in its own database. Microsoft Corporation's DUNS is 081166849. These numbers are publicly searchable through the D&B directory:

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Microsoft Corporation",
  "url": "https://www.microsoft.com",
  "duns": "081166849"
}

The ISO 6523 equivalent (ICD 0060) for the same identifier:

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Microsoft Corporation",
  "iso6523Code": "0060:081166849"
}

Related fields

• iso6523Code
• leiCode
• taxID
• globalLocationNumber
• vatID

FAQ

Is DUNS still relevant after the SAM.gov changes?

Yes. The US federal government migrated from DUNS to the UEI (Unique Entity Identifier) system managed by SAM.gov in 2022 for federal contracting purposes. However, DUNS numbers remain widely used in commercial databases, supply chain systems, credit rating, and B2B procurement outside of federal government contexts. The schema.org duns property remains valid and Google continues to recommend it.

What is a D&B corporate family tree?

D&B assigns each DUNS number a corporate linkage showing domestic ultimate, global ultimate, and subsidiary relationships. This hierarchical structure is part of what makes DUNS numbers valuable for AI systems: they do not just identify a single entity but also expose its corporate ownership chain. Schema.org does not model this hierarchy directly, but a DUNS number gives AI systems a path to retrieve it from D&B.

Should I use duns or iso6523Code?

Google recommends iso6523Code as the preferred format. If you are implementing from scratch, use iso6523Code with ICD 0060 for the DUNS value. If you already have duns in your schema markup, it remains valid and does not need to be replaced.