United States · Business identifiers
DUNS number format: nine digits, and what replaced it.
Check that a number has the published D-U-N-S shape, and see what federal systems use now that the DUNS number is gone from them.
Short answer: A D-U-N-S number is a nine-digit identifier issued by Dun & Bradstreet. Federal systems stopped using it on April 4, 2022 and now use the 12-character SAM.gov Unique Entity ID, but D&B still issues D-U-N-S numbers and says many agencies and companies still use them.
Check a number’s shape
Result
Enter a number and press Check.
The published shape
GSA’s stakeholder slides from November 3, 2021 describe the DUNS number as a 9-character numeric value that is managed, granted and owned by Dun & Bradstreet. Dun & Bradstreet’s own D-U-N-S page calls it a unique nine-digit identifier used exclusively for businesses. Both agree: nine digits, no letters.
Neither source describes a check digit or any other internal structure, so this page checks only the length and the character set. A number that passes is shaped like a D-U-N-S number; it may or may not have been issued, and other nine-digit numbers look identical.
What changed on April 4, 2022
The same GSA slides say the DUNS number would remain the authoritative federal identifier until April 3, 2022, and that from April 4, 2022 the Unique Entity ID (SAM) would take over. The UEI is a 12-character alphanumeric value, managed, granted and owned by the government. GSA’s fact sheet adds that DUNS numbers would no longer be accepted or visible at GSA’s sites from that date, and that anyone with saved reports or searches built on DUNS fields should switch to UEI fields.
What Dun & Bradstreet still does
Dun & Bradstreet’s page says getting a D-U-N-S number is free and points to a D-U-N-S Lookup tool for finding your own number or another company’s. It says organisations may use the number to evaluate business credit, keep records, onboard a company and maintain compliance. On government work it says a D-U-N-S number is not required for US federal government contracts, but many other agencies, governments and companies around the world still use it.
Open Dun & Bradstreet’s D-U-N-S page ↗
Worked example (made-up values)
123456789 is nine digits, so it passes. 12-345-6789 passes too, because hyphens and spaces are ignored. 12345678 fails: eight digits. 1234567890 fails: ten digits. 12345678A fails because of the letter. And J6H4FB3N5YK4 is flagged differently: it has the shape of a 12-character UEI, which is the identifier federal systems use now, so the tool points you to the UEI validator instead of calling it a bad DUNS number.
Method
The tool upper-cases what you type, removes spaces and hyphens, and applies fixed rules: exactly nine digits is a match for the DUNS shape; twelve letters and digits with no I or O and no leading zero is reported as UEI-shaped; anything else fails with the reason. Nothing is sent to our servers.
What this does not cover
- Whether a number was issued, which business it belongs to, or whether it is current. Use Dun & Bradstreet’s lookup for that.
- Any structure inside the nine digits. None is published in the sources read, and none is checked.
- Branch, headquarters or parent relationships between numbers, which Dun & Bradstreet manages.
- Your SAM.gov registration. Search SAM.gov for the entity’s UEI and status.
Sources
- GSA, Getting a Unique Entity ID (SAM), stakeholder meeting slides, Nov 3 2021 (retrieved October 2026)
- GSA, Transitioning to the New Unique Entity ID (SAM) fact sheet (retrieved October 2026)
- Dun & Bradstreet, D-U-N-S Number questions (retrieved October 2026)
Common mix-ups
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Often assumedFederal contracting and grant systems still identify businesses by DUNS number.
What the source saysGSA's fact sheet says that on April 4, 2022 the D-U-N-S number was removed and the Unique Entity ID (SAM) became the authoritative identifier, and that DUNS numbers would no longer be accepted or visible at GSA's sites. [1]
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Often assumedA UEI is just a new DUNS number.
What the source saysGSA's slides describe the DUNS number as a nine-character numeric value owned by Dun & Bradstreet, and the Unique Entity ID as a 12-character alphanumeric value managed, granted and owned by the government. [2]
- GSA: Transitioning to the New Unique Entity ID (SAM) fact sheet
- GSA: Getting a Unique Entity ID (SAM), stakeholder slides, Nov 3 2021
Checked against these sources on .
Frequently asked questions
How many digits is a DUNS number?
Nine. GSA describes it as a 9-character numeric value and Dun & Bradstreet calls it a unique nine-digit identifier.
Can a DUNS number contain letters?
No. Both GSA and Dun & Bradstreet describe it as numeric. A value with letters is not a D-U-N-S number.
Does the federal government still use DUNS numbers?
No. GSA’s slides say the Unique Entity ID (SAM) became the authoritative federal identifier on April 4, 2022, and Dun & Bradstreet says a D-U-N-S number is not required for US federal government contracts.
What is the difference between a DUNS number and a UEI?
A DUNS number is nine digits and is owned by Dun & Bradstreet. A UEI is 12 letters and digits and is owned by the government, according to the same GSA slides.
Do I still need a DUNS number?
Not for US federal contracts, per Dun & Bradstreet. It says many other agencies, governments and companies still use it, so a customer or lender may still ask for one.
Does getting a DUNS number cost money?
Dun & Bradstreet’s page says getting a D-U-N-S number is free. Be wary of any site that charges for it.
Does this tool confirm my DUNS number is real?
No. It checks the shape only. Use Dun & Bradstreet’s D-U-N-S Lookup to find or confirm a number.
Shape only
A nine-digit value is not proof that a D-U-N-S number was issued or belongs to the business in front of you. This page is an unofficial guide, not run by Dun & Bradstreet or GSA, and nothing you type is transmitted anywhere. General information, not legal or compliance advice.