Short answer
The United States has no single national company registration number. A US company gets its registration number from the state where it registered. Delaware calls it a file number, Wyoming a Filing ID, Florida a document number, and New York a DOS ID. The EIN is a federal tax ID from the IRS. The DUNS number comes from Dun & Bradstreet. If a form does not say which number it wants, ask the company that sent it.
Key takeaways
- There is no national company register in the US. State offices register companies, and each state gives its own number.
- Delaware defines its file number as “A unique identifier assigned to each entity incorporated, formed, qualified or registered with the Division of Corporations.”
- You can find the state number by searching the company name in the state’s business search. Delaware, Wyoming, and New York all point to their search for this.
- The IRS says “An EIN is a federal tax ID number for businesses, tax-exempt organizations and other entities.” The EIN comes from the IRS, and the state number comes from the state.
- Dun & Bradstreet calls the D-U-N-S Number “a unique nine-digit identifier used exclusively for businesses.” Dun & Bradstreet is a private company, not a government registry.
- Florida’s fictitious name form asks for an owner company’s state registration number and its federal tax number in two separate fields. If a form you receive does not say which number it wants, ask the company that sent it.
Does the US have a company registration number?
The United States has no single national company registration number. Companies are registered by state offices, and each state gives the companies on its records its own number. So the number a form calls a “company registration number” is the number from your state record.
The National Association of Secretaries of State describes the job on its corporate registration page. It says “Most NASS member offices handle the registration of domestic and/or foreign corporations (profit and non-profit).” A domestic company is one formed in that state. A foreign company is one formed in another state that registers to do business there. The same NASS corporate registration page links to the business registration page of each state.
Some forms ask for a company registration number because the country that wrote the form has one national register. A US company does not have that kind of number. It has a state number, a federal tax number, and sometimes a private number from a data company. The next sections explain each one.
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What each state calls the number
Each state uses its own name for the number. The four states below show how different the names can be. Other states use other names, so check the wording on your own state’s filing records.
Delaware calls it a file number. The Delaware Division of Corporations defines it on its entity search field guide as “A unique identifier assigned to each entity incorporated, formed, qualified or registered with the Division of Corporations.” The definition covers companies formed in Delaware and companies from other states that registered there.
Wyoming calls it a Filing ID. The Secretary of State’s annual report page lists what you need to file. Its list starts with “Secretary of State Filing ID. If you don't have the Filing ID, use the Search option.”
Florida calls it a document number. The state’s fictitious name application has a field labeled “Florida Document Number” for an owner that is a company. The form’s instructions describe the same field as “their registration number as registered with the Division of Corporations.”
New York calls it a DOS ID number. DOS stands for Department of State. The Department’s biennial statement page says that to file online “you must have the exact name of the entity and its DOS ID number.”
| State | Name the state uses | Where the state uses that name |
|---|---|---|
| Delaware | File number | Division of Corporations entity search field guide |
| Wyoming | Filing ID | Secretary of State annual report page |
| Florida | Florida Document Number | Fictitious name application, form CR4E001 |
| New York | DOS ID number | Department of State biennial statement page |
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How to find your company’s state number
The state’s own business search is the place to look. Delaware, Wyoming, and New York each point you there.
Delaware’s FAQ says “We offer the ability to search for a business entity on the web by name or file number.” It also says “The entity information provided free of charge, includes the entity name, file number, incorporation/formation date, registered agent name, address and phone number along with the entity kind, type, and residency.” The same FAQ says “Search results will return both active and inactive entities, however, this does not provide entity status.”
Wyoming’s annual report page says to “use the Search option” if you do not have the Filing ID. New York says the exact name and the DOS ID number “may be found by searching the name of the entity on the Department of State’s Corporation & Business Entity Database.”
If your company is registered in more than one state, it has a record in each of those states. Each record can have its own number. Write the state name next to the number on any form, so the reader knows which registry to search.
- 1Find the business search on the website of the state office that keeps your company’s records. The NASS corporate registration page links to each state.
- 2Search for your company by its exact legal name.
- 3Open your company’s record and copy the number the state shows for it.
- 4Check that the name and state on the record match your company before you use the number.
The EIN is a federal tax ID number
The EIN, or Employer Identification Number, comes from the Internal Revenue Service. The IRS EIN page says “An EIN is a federal tax ID number for businesses, tax-exempt organizations and other entities.” The state that registered your company does not issue it.
Many forms ask for the EIN in a field named tax ID or taxpayer identification number. The state number and the EIN are two different numbers from two different offices. Florida’s fictitious name form shows the difference well. It asks for an owner company’s registration number with the Division of Corporations, and it asks for the Federal Employer Identification (FEI) number in a separate field.
The IRS lists three ways to confirm your EIN. You can request an entity transcript. Eligible Business Tax Account users can download a digital CP575, the EIN verification notice. You can also call the IRS business and specialty tax line and request Letter 147C. Our guide to the EIN 147C letter explains how to request that letter.
The DUNS number is a private business number
The D-U-N-S Number comes from Dun & Bradstreet, a private company. Dun & Bradstreet’s D-U-N-S Number page says “The Dun & Bradstreet D‑U‑N‑S Number is a unique nine-digit identifier used exclusively for businesses.” The same page says “Getting a D‑U‑N‑S Number is free.”
Dun & Bradstreet says other organizations “may use your D-U-N-S Number to evaluate your business credit profile, maintain their records, onboard your company, and maintain compliance.” The number does not come from a government registry. A form that asks for a company registration number is asking about a government record, so a DUNS number is a separate answer to a separate question.
The page also says “A D-U-N-S Number isn't required for U.S. federal government contracts.” Our guide to DUNS and UEI explains which number federal systems use now.
Which number to give when a form asks
Match the number to the office that issued it. Read the field label and any help text on the form before you type anything.
Some forms ask for a registered address next to the registration number. In Delaware, the free state record lists the registered agent’s name, address, and phone number. If the form does not say which address it wants, ask the company that sent the form. Our guide to US company registration for non-residents explains how the state filing, the EIN, and the business address fit together.
A form may also ask for proof that the company exists and is active. A number alone does not show the company’s status. Our guide to the certificate of good standing explains the state document that does.
| Field on the form | Number to give | Who issues it |
|---|---|---|
| Company registration number, registry number, or state file number | The number on your company’s state record, with the state name | The state office that registered the company |
| Tax ID, taxpayer identification number, or EIN | Your EIN | The IRS |
| D-U-N-S Number | Your D-U-N-S Number | Dun & Bradstreet |
| Field with no clear label | Ask the company that sent the form | Not known from the form |
Not legal or tax advice
This guide summarizes the Delaware, Wyoming, Florida, New York, IRS, NASS, and Dun & Bradstreet pages cited here, as read on October 31, 2026. Field names and search tools can change. Ask the bank, platform, or registry that sent your form which number it needs, and ask a professional about your own company.
Frequently Asked Questions
Sources & References
Primary sources this guide is based on.
- 1National Association of Secretaries of State · Corporate Registration (accessed October 31, 2026)
- 2Delaware Division of Corporations · Entity Search Field Descriptions (accessed October 31, 2026)
- 3Delaware Division of Corporations · Frequently Asked Questions (accessed October 31, 2026)
- 4Wyoming Secretary of State · Annual Report (accessed October 31, 2026)
- 5Florida Department of State, Division of Corporations · Application for Registration of Fictitious Name (CR4E001) (accessed October 31, 2026)
- 6New York Department of State · Biennial Statements for Business Corporations and Limited Liability Companies (accessed October 31, 2026)
- 7Internal Revenue Service · Employer identification number (accessed October 31, 2026)
- 8Dun & Bradstreet · D-U-N-S Number Questions: Start Here (accessed October 31, 2026)
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I'm Henry, a hedgehog in a bow tie who explains the dull, scary parts of building and running a U.S. business.
