How to Check and Verify a DUNS Number (Step-by-Step)
A DUNS number is only useful if it is accurate and belongs to the right entity. Whether you are verifying your own number before submitting a government application or checking a vendor's credentials before signing a contract, knowing how to properly verify a DUNS number can save you from costly mistakes.
This guide walks you through the entire verification process, the tools available, and the warning signs to watch for.
Why Verify a DUNS Number?
Verifying a DUNS number is not just a formality. There are real, practical reasons to confirm that a DUNS number is valid and correctly linked to the right business:
- Government compliance. If you are registering in SAM.gov or applying for a federal grant, an incorrect DUNS number will delay or block your application. The government cross-references DUNS data with your registration details, and mismatches cause rejections.
- Vendor due diligence. Before signing a contract with a new supplier, verifying their DUNS number lets you confirm they are a real, established business. You can also use the DUNS number to pull credit reports and assess financial risk.
- Business credit accuracy. Your DUNS number is tied to your Dun & Bradstreet credit file. If the data attached to your number is wrong --- incorrect address, outdated employee count, wrong SIC code --- it can hurt your business credit score and your ability to win contracts.
- Fraud prevention. In procurement and contracting, fraudulent entities sometimes provide fake or stolen DUNS numbers. Verification helps you catch this before money changes hands.
- Merger and acquisition diligence. During M&A processes, verifying the target company's DUNS number confirms their corporate identity and reveals their D&B credit history and corporate family structure.
How to Verify Your Own DUNS Number
If you are checking your own business's DUNS number, the goal is to make sure the number exists, is active, and that all the linked data is correct.
Step 1: Look Up Your Number
If you do not have your DUNS number readily available, start by finding it:
- Search our free DUNS lookup tool. Enter your business name and location to retrieve your number.
- Check old documents. Your DUNS number may appear on previous government registrations, Apple Developer enrollment confirmations, credit applications, or correspondence from D&B.
- Call D&B. If you cannot find it through a search, contact D&B's customer support at their business verification line. You will need to verify your identity as an authorized representative of the business.
Step 2: Review the Linked Data
Once you have your DUNS number, check that the following information is accurate:
- Legal business name --- Does it match your current legal name exactly, including correct spelling, punctuation, and entity type (LLC, Inc., Corp., etc.)?
- Physical address --- Is this your current business location? If you have moved, the old address may still be on file.
- Phone number --- Is the number current and reachable?
- Number of employees --- Is the figure reasonably accurate? Large discrepancies can affect your credit profile.
- Industry codes --- Are the SIC and NAICS codes correct for your actual business activity?
- Corporate family structure --- If you are a subsidiary, is your parent company correctly linked? If you are an independent business, make sure no parent company is incorrectly listed.
Step 3: Correct Any Errors
If any information is wrong, you need to update it with D&B. The process varies depending on the type of change, but generally involves contacting D&B or submitting updates through their online portal. For detailed instructions, see our guide on how to update or change your DUNS number information.
How to Verify a Vendor's or Partner's DUNS Number
When someone gives you a DUNS number --- on a bid, a contract, or a business proposal --- you should verify it independently rather than taking it at face value.
Step 1: Search the Number Directly
Use our free DUNS lookup tool to search for the DUNS number. This will return the business name and address associated with that number.
Step 2: Cross-Reference the Results
Compare the lookup results against the information the vendor provided:
- Does the business name match exactly? Minor variations (like "Corp" vs "Corporation") can be normal, but a completely different name is a red flag.
- Does the address match the vendor's known address? Keep in mind that DUNS numbers are location-specific, so a company may have different numbers for different offices.
- Is the business active? An inactive or deactivated DUNS record suggests the company may have closed.
Step 3: Pull a Credit Report (Optional but Recommended)
For high-value contracts or new vendor relationships, go beyond the basic lookup. D&B offers paid credit reports that include:
- Paydex score (D&B's payment-based credit score, ranging from 1 to 100)
- Financial stress score and failure risk
- Payment history with other suppliers
- Legal filings (liens, judgments, bankruptcies)
- Company financials (if reported)
This information is tied to the DUNS number and gives you a much clearer picture of the vendor's financial health. Learn more in our article on DUNS numbers and business credit.
Using Our Free Lookup Tool for Verification
Our DUNS number lookup tool is designed specifically for quick verification. Here is how to get the most out of it:
- Search by company name if you want to find or confirm a DUNS number.
- Search by DUNS number if you already have the number and want to confirm which business it belongs to.
- Add location details to narrow results when the company name is common. Including the city and state will filter out unrelated matches.
- Review all returned matches carefully. Large companies may have dozens of DUNS numbers (one per location). Make sure you are looking at the correct branch, division, or headquarters.
Using D&B's Official Tools
For additional verification depth, D&B provides several tools:
D&B Business Search
D&B's website offers a basic search where you can look up businesses and view limited DUNS data. This is the most authoritative source since D&B maintains the database, but the free tier is limited and the site pushes paid products.
D&B Credit Reports
Paid reports (starting around $50--$150 per report depending on the level of detail) provide comprehensive business credit data. For ongoing vendor management, D&B offers subscription-based monitoring that alerts you to changes in a company's credit profile.
D&B Direct and D&B Hoovers
For businesses that need to verify DUNS numbers in bulk or integrate verification into their procurement workflows, D&B offers API access (D&B Direct) and a research platform (D&B Hoovers). These are enterprise-grade tools with enterprise-grade pricing, but they are the gold standard for organizations that do large-scale vendor management.
What Information a DUNS Lookup Reveals
A standard DUNS lookup returns:
| Data Point | Description |
|---|---|
| DUNS Number | The unique 9-digit identifier |
| Business Name | Legal name and any trade names (DBAs) |
| Physical Address | Street address of the business location |
| Phone Number | Primary business phone |
| Employee Count | Number of employees at that location and company-wide |
| Annual Revenue | Estimated or reported revenue |
| Year Started | When the business began operating |
| SIC/NAICS Codes | Industry classification codes |
| Corporate Linkage | Parent company, headquarters, branches, and subsidiaries |
This information is publicly available through free lookup tools. Detailed financial data, credit scores, and payment histories require paid access.
Red Flags to Watch For
When verifying a DUNS number, these warning signs suggest something may be wrong:
The Number Does Not Exist
If a DUNS number search returns no results, the number is either fake, was entered incorrectly, or belongs to a deactivated record. Ask the vendor to provide documentation showing their DUNS assignment from D&B.
The Name Does Not Match
If the DUNS number returns a different company name than what the vendor provided, this is a serious red flag. It could be an honest mistake (wrong number provided) or an attempt to impersonate another business.
The Address Is a Residential Home or PO Box
While some legitimate small businesses operate from home addresses, a DUNS record showing a residential address for a company claiming to be a large operation warrants further investigation.
Very Recent Establishment Date
A DUNS record showing the business was established very recently, combined with claims of years of experience, suggests the entity may not be what it claims. A new DUNS number does not always mean a new business (companies sometimes register late), but it should prompt further questions.
No Employees or Revenue Listed
A DUNS record with zero employees and no revenue may indicate a shell entity or a record that was never properly updated. Ask the vendor to explain and consider requesting updated D&B data.
Multiple Records for the Same Entity
If you find several DUNS numbers that all seem to belong to the same business at the same address, the entity may have duplicate records. This is a data quality issue rather than fraud, but it can cause confusion. The business should contact D&B to resolve duplicates.
Frequently Asked Questions
Can I verify a DUNS number for free?
Yes. Our free lookup tool lets you verify that a DUNS number exists and view the basic business information associated with it. For detailed credit data, you would need a paid D&B report.
How often should I verify vendor DUNS numbers?
For critical suppliers and high-value contracts, verify DUNS data at least annually and before renewing any major agreements. Companies move, change names, and sometimes close --- your records should reflect current reality.
What if a vendor refuses to provide their DUNS number?
A refusal to provide a DUNS number is unusual in professional contracting and may be a red flag. For government contracts, it may be a disqualifying issue. For private contracts, you can look up the number yourself using the company name and address via our lookup tool.
How do I know if a DUNS number is still active?
If a DUNS number returns results in a lookup search, the record is active. If it returns no results, the record may have been deactivated. Contact D&B for confirmation on deactivated records.
Need to verify a DUNS number right now? Use our free lookup tool for instant results. For background on what DUNS numbers are and why they matter, visit our what is a DUNS number page.