USA company registration number: Essential guide for founders
Content Team
Summary
The US has no single national company registration number. A state entity or file number identifies your company in a state registry, while the EIN is a federal tax ID from the IRS. The identifier requested depends on how the organization defines “company registration number”
An EIN is a 9-digit number in the format XX-XXXXXXX. Corporations and partnerships generally need an EIN, as do businesses with employees or certain federal tax obligations. If you don’t need one for federal tax, you can still get one for banking or state tax, and many banks ask for one when you open a business account
When a state accepts your LLC or corporation filing, its filing office generally assigns an entity, file, or charter number. If you register in another state, that state usually assigns its own number
Use your EIN for federal tax filings and payroll, and for business banking when your bank asks for it. Use your state entity number for state registration records, annual reports, and any other filing that asks for it specifically
Find your EIN on your IRS assignment notice or past federal tax returns. Find your state number on your filed formation documents or by searching your state's business registry
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The US doesn’t have a single national company registration number. Each state runs its own registry, and when yours accepts your formation filing, it gives your company an entity or file number. That’s one identifier a form may mean by “company registration number.” Your Employer Identification Number (EIN) is a separate federal tax ID from the IRS.
Corporations generally have both. Many LLCs do too, though a single-member LLC may not need an EIN for federal tax purposes. It can still get one for banking or state tax requirements.
Not every bank, vendor, or payment provider uses the term the same way. Some mean a tax ID, incorporation number, or another identifier, so confirm what they’re asking for before you enter your EIN.
In this article, find out which US business identifiers you’ll come across, how to get each one, and when banks, partners, and agencies ask for them.
Key differences between employer identification number and state entity number
The IRS issues one. Your state issues the other. Here’s how they compare:
| Aspect | Employer Identification Number (EIN) | State Entity Number |
|---|---|---|
| Issuing authority | Internal Revenue Service (IRS) | The state’s filing office, usually the Secretary of State |
| Primary purpose | Identifying a business for federal tax and IRS reporting | Identifying a business for state registration, compliance, and filings |
| Where you need it | Federal tax returns, payroll tax filings, and bank onboarding | Annual reports, amendments, certificates of status or good standing, and other state filings |
| Who needs it | Corporations, partnerships, multi-member LLCs, employers, and certain single-member LLCs | LLCs, corporations, and other entities formed or registered with a state |
| Format | 9 digits, formatted as XX-XXXXXXX | Varies by state; numeric, alphanumeric, and different lengths |
| How to get it | From the IRS, online, by fax, or by mail | Assigned by the state filing office when it accepts your formation or registration filing |
| Number of identifiers per business | One per entity in most cases. Certain ownership or structure changes require a new EIN | One per state where the entity is formed or registered |
| Banking and payroll | Many banks ask for an EIN to open a business account, and employers use it for payroll tax filings | Banks may ask for it to verify your registration. State payroll taxes use a separate state employer account number |
Your EIN generally stays with your company when it expands into another state. Certain changes to your company’s ownership or legal structure do require a new EIN.
What is an employer identification number?
An EIN is your company’s federal tax ID. The IRS assigns it as a 9-digit number in the format XX-XXXXXXX. You’ll still have a separate state registration number.
You need one if you hire employees, run a corporation or partnership, or file employment or excise tax returns. Many banks also ask for an EIN when you open a business account, and lenders often request it on loan applications.
How to get an EIN
Apply for an EIN online, by fax, or by mail. International applicants can also apply by phone. Which method you can use depends on where your business is located and whether you have an SSN or ITIN. If you’ve lost your EIN, you can find it in your IRS records or other business documents.
Company registration number vs EIN
The IRS issues your EIN as a federal tax ID. The state where you form or register your company issues its business registration number. People sometimes use “business registration number” for either one, but you can’t use one in place of the other.
Say you form an LLC in Delaware. It can have one federal EIN and a separate Delaware file number. Register it in California later, and California usually gives it another entity number. The EIN doesn’t change.
State registration numbers and company IDs
Every US state runs its own business registry. To form a corporation, you file articles of incorporation. For an LLC, it’s articles of organization. Once the state accepts your filing, its filing office generally assigns your company a unique number in that registry. The same record may show whether the entity is active, inactive, dissolved, or in good standing.
The name of this number depends on the state. Delaware and Texas call it a file number, California uses an entity number, Florida uses a document number, and Washington uses a Unified Business Identifier, or UBI. Formats vary too. Some states use only digits, while others mix in letters.
- Your state entity number isn't a state tax ID. If you hire or sell taxable goods in a state, you'll usually register separately with that state's revenue or labor agency to handle payroll taxes and sales tax.
The SBA's state registration lookup links to the official registration office for every state and territory. Here's where to search in a few states founders often register in:
| What the number is called | Official business search |
|---|---|
| SOS ID | https://sosnc.gov/online_services/search/by_title/search_Business_Registration |
| Texas file number | https://www.sos.state.tx.us/corp/sosda/index.shtml |
| Document number | https://dos.fl.gov/sunbiz/search/ |
| SCC ID (State Corporation Commission ID) | https://cis.scc.virginia.gov/EntitySearch/Index |
| Entity number | https://ohio.gov/business/resources/business-search |
| CID number (Corporate Identification Number) | https://www.michigan.gov/lara/bureau-list/cscl/corps |
| Entity number | https://bizfileonline.sos.ca.gov/search |
| DOS ID (Department of State ID) | https://dos.ny.gov/corporation-and-business-entity-search-database |
| File number | https://apps.ilsos.gov/businessentitysearch/ |
| UBI (Unified Business Identifier) | https://ccfs.sos.wa.gov/ |
How long a filing takes depends on the state, how you file, and whether you pay for faster service. Check the state filing office for current estimates. After that, you’ll use your entity number for annual reports, amendments, other state filings, and any request to verify your registration. If you expand into more states, each one gives you a separate number.
How to find a USA company registration number
How you find a US business registration number depends on which identifier you need and whether you’re looking for your own or another company's:
Step 1: Ask what they need. It could be an EIN, a state entity number, a tax account number, or a license ID.
Step 2: Check your documents. If you're looking for your own company's number, it's on your formation filings or IRS records.
Step 3: Search official databases. Use these when you need another company's number or can't find your own paperwork.
Here’s where to find a business registration number for your own company or someone else’s:
Searching for your own business
The IRS and your state each send you paperwork once they process your applications. Here’s where to find each number:
- Check your IRS EIN assignment notice: Online applicants can view, print, and save it at the end of the application session. Fax and mail applicants receive their EIN from the IRS by fax or mail
- Review your business tax returns: Your EIN appears on every federal tax return you've filed, including Form 1120 for C corporations, Form 1120-S for S corporations, and Form 1065 for partnerships
- Look at your filed articles of incorporation or organization: The filed copy the state returns after accepting your formation documents usually shows your entity or file number
- Check annual report confirmations: If you've filed annual reports with your state, the confirmation emails or letters include your state registration number
Searching for another business
Several online databases can help you find another company’s registration number:
- Public companies: Search SEC EDGAR by company name to see its filings and Central Index Key, or CIK. The CIK is an SEC filer ID, not a state registration number, so use the state registry for the company's entity number
- Private companies: Go to the business search on the Secretary of State or other state registration authority for the state where the company is registered
- Nonprofits: If an organization is recognized as tax-exempt under Section 501(c) of the Internal Revenue Code, use the IRS Tax-Exempt Organization Search tool to verify its tax-exempt status and find its EIN. To confirm its state incorporation or registration, check the state registry
- Third-party databases: Aggregators like OpenCorporates pull registry data from US states and other countries into one search. They help when you don't know where a company is registered, but always confirm the details in the official state registry
An official state registry record typically shows:
- Exact legal name
- State of formation
- Entity or file number
- Formation date
- Current status
- Registered agent
- Entity type, such as LLC or corporation
Before you rely on a record, check that the legal name and state match the details the company gave you. If the company operates in several states, its home state is where it was formed, and each state where it registered to do business may hold a separate record with its own number.
Specialized identifiers and when you need them
Some forms ask for other numbers that people often mistake for a company registration number. None of these replaces your state entity number or EIN:
| How it differs from an EIN or state entity number | Issuing authority | Who needs it | Where it is required |
|---|---|---|---|
| Identifies individuals, not businesses, for Social Security | Social Security Administration (SSA) | Sole proprietors without an EIN | Federal tax filings and some banking requirements. It’s often used temporarily until the IRS issues an EIN |
| A tax processing number for people who aren’t eligible for an SSN | IRS | Non-US owners without SSNs | Federal tax reporting. It doesn’t replace an EIN |
| Used for state tax administration. Your state entity number covers forming and registering the business | State Department of Revenue/Taxation | Businesses with state tax obligations | Sales, income, and franchise tax filings |
| Authorizes a business to collect and remit sales tax. It isn’t proof of business registration | State tax authority | Businesses selling taxable goods/services | Collecting and remitting sales tax. It’s required along with the EIN |
| Lets employers report and pay state income tax withheld from employee wages | State labor or revenue agency | Employers with in-state employees | State payroll tax filing |
| DUNS is a credit reporting and identification number. It isn’t a registration number | Dun & Bradstreet (private) | Businesses seeking credit or a contract | Vendor onboarding, federal grants, enterprise sales |
| Used for federal contracts and grants, not taxes or business registration | US federal government (SAM.gov) | Businesses working with federal agencies | Federal contracts, grants, payments, etc. |
| Issued to a business or individual to legally practice a licensed profession (e.g., healthcare, legal, engineering) | State licensing board | Regulated professions | Legal operations of licensed services like doctors, CPAs, lawyers, and architects |
| A federal- or state-issued license that authorizes regulated activities and is separate from tax or entity registration | Federal or state regulator | Regulated industries | Compliance and reporting from specific industries |
| Identifies FDA-regulated facilities for oversight, not for tax filing or business formation | Food and Drug Administration (FDA) | Food, medication, and medical devices businesses | Manufacturing, distribution, and import of regulated products |
| It identifies businesses that manufacture, import, or distribute textile, wool, or fur products | Federal Trade Commission (FTC) | Textile, wool, and fur businesses | Product labels, in place of the business name |
Why banks, agencies, and partners ask for these numbers
Government agencies, financial providers, and business partners may use these identifiers to match the company to official records. The identifier requested depends on the task and authority.
KYB verification for accounts and payments
When you're applying for a business bank account, setting up a payment processor, or partnering with another company, they'll verify your business using these identifiers. Financial institutions use them to perform compliance checks.
Banking, hiring, and contracts
Many banks ask for an EIN when you open a business bank account, and you need one before you hire employees. If you are applying for a business credit card, you commonly require an EIN. You may require your state registration number for any legal contracts, real estate transactions, or state-level licenses.
Compliance and reporting
Tax authorities, regulators, and licensing boards use these numbers to match filings to your company. If you change your business address, legal structure, or ownership, update your records with each agency that holds them, such as the IRS, your state filing office, your state tax agency, or a licensing board. The filing you need depends on the type of change. Keeping your numbers on hand also makes it easier to respond to tax notices and file annual reports on time, which keeps your company in good standing.
Cross-border payments and partners
Overseas banks, payment providers, and partners may ask for different identifiers to confirm your company exists in the US. Check which identifier they mean before providing your state entity number or EIN, and include your state of formation when relevant.
Final thoughts
When a form asks for your USA company registration number, first check which identifier the requester means. It may be your state entity or file number, but some organizations may use the field for a tax ID, incorporation number, or another jurisdiction-specific identifier. Check what the requester means, then confirm the number against your filed formation documents or the official state registry before you submit it. If the form asks for a federal tax ID, that’s your EIN, which you’ll find on your IRS assignment notice or past tax returns.
Opening a US business account is often the first time you’ll need both numbers. Aspire’s US business account¹ asks for your company details during onboarding, so keeping your filed articles, state entity number, and EIN notice together saves you a search later.
Frequently Asked Questions
A business registration number is an informal term for an official identifier connected to a company record. In the US, it may refer to a federal EIN, a state entity or file number, or another government-issued account number. The correct identifier depends on the task and issuing authority.
The term “company registration number” can be used for either EIN or state registration number. EIN is a federal tax identifier, where for states, you may require the state registration number.
A business registration number search can help confirm the vendor’s recorded legal name, jurisdiction, formation date and entity status. It should be used alongside broader commercial due diligence and does not eliminate fraud risk.
If you are searching for your state registration number, you can check your state’s official business registry, or your formation documents, registration certificate, or annual filing conformation. If you are looking for your EIN instead, check your IRS EIN confirmation letter, federal tax returns, or IRS notices.
To find your company’s EIN, check the IRS assignment notice, previously filed federal tax returns, payroll records and earlier business-account or credit applications. Use the IRS’s official retrieval process if you still cannot locate it.
No, the US does not have one company register. Businesses are registered at a federal and state level so every state maintains its own registry. The IRS issues EIN, but does not maintain a public national registry of all registered businesses.
Non-US founders can form certain US business entities and may apply for an EIN. The application method and documentation depend on the applicant and the responsible party. State formation generally requires a registered agent in the relevant state, which is separate from the founder’s personal address.
The EIN that the IRS issues does not expire or get reassigned; it remains associated with the company. However, if your business closes, the IRS may choose to close the business account as well; even so, the EIN number will remain associated with your business. A state registration number does not really expire, but a business can lose its active status if it fails to file its tax obligations or annual reports.
A sole proprietor operating under their legal name may not need a state entity number, although tax accounts, permits, or licenses may still apply. Forming an LLC or corporation creates a separate legal entity and generally results in a state-issued entity number. A DBA is a separate assumed-name registration.
To form a company in the US, requirements vary by state and entity type. Common filings can include articles of incorporation or organization, registered-agent information, and state-specific ownership or management details. Consult the relevant state formation guide for the complete requirements.
Sources
- https://www.irs.gov/businesses/small-businesses-self-employed/get-an-employer-identification-number (https://www.irs.gov/businesses/small-businesses-self-employed/get-an-employer-identification-number), 16 Oct 2026
- https://www.irs.gov/instructions/iss4 (https://www.irs.gov/instructions/iss4), 30 Apr 2026
- https://www.irs.gov/businesses/small-businesses-self-employed/when-to-get-a-new-ein (https://www.irs.gov/businesses/small-businesses-self-employed/when-to-get-a-new-ein), 21 Jul 2026
- https://www.irs.gov/newsroom/how-to-get-an-employer-identification-number-for-your-business (https://www.irs.gov/newsroom/how-to-get-an-employer-identification-number-for-your-business), 10 Aug 2026
- https://www.taxpayeradvocate.irs.gov/get-help/general/getting-an-ein/ (https://www.taxpayeradvocate.irs.gov/get-help/general/getting-an-ein/), 22 Apr 2026
- https://www.irs.gov/charities-non-profits/search-for-tax-exempt-organizations (https://www.irs.gov/charities-non-profits/search-for-tax-exempt-organizations), 16 Sp 2026
- https://www.sba.gov/counseling/launch-your-business/state-registration-lookup/ (https://www.sba.gov/counseling/launch-your-business/state-registration-lookup/), 20 Oct 2026
- https://www.sec.gov/search-filings (https://www.sec.gov/search-filings), 20 Oct 2026
- https://www.sec.gov/submit-filings/filer-support-resources/how-do-i-guides/look-central-index-key-cik-number (https://www.sec.gov/submit-filings/filer-support-resources/how-do-i-guides/look-central-index-key-cik-number), 31 Oct 2024
- https://www.ftc.gov/business-guidance/industry/registered-identification-number-frequently-asked (https://www.ftc.gov/business-guidance/industry/registered-identification-number-frequently-asked), 20 Oct 2026
- https://icis.corp.delaware.gov/eCorp/EntitySearch/NameSearch.aspx (https://icis.corp.delaware.gov/eCorp/EntitySearch/NameSearch.aspx), 20 Oct 2026
- https://www.sos.ca.gov/business-programs/business-entities/cbs-search-tips (https://www.sos.ca.gov/business-programs/business-entities/cbs-search-tips), 20 Oct 2026
- https://search.sunbiz.org/Inquiry/CorporationSearch/ByName (https://search.sunbiz.org/Inquiry/CorporationSearch/ByName), 20 Oct 2026
- https://mt.usembassy.gov/determining-if-a-company-is-registered-in-the-u-s/ (https://mt.usembassy.gov/determining-if-a-company-is-registered-in-the-u-s/), 20 Oct 2026
This blog is for general information only and does not constitute financial, legal, tax, or professional advice. Aspire’s services are subject to the terms outlined in our ’Terms of Service’ and ’Pricing’ pages. We make no guarantees as to the accuracy, completeness, or timeliness of the content, and past results do not indicate future performance. Always consult a qualified professional before acting on any information provided.
Content Team
Aspire editorial
Content team at Aspire is a society of seasoned writers & experts specialising in finance, technology and SaaS space. With 50+ years of collective experience, they help make business finance more profitable for readers. They write about finance tools, finance insights, industry trends, tactical guides to grow your business & also all things Aspire.
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