
For massive corporations, small LLCs, and everyone in between, the moment your business is officially registered, the state of Delaware gives it a single, permanent identifier: the Delaware state file number. This number is a critical key for maintaining your legal status, paying annual taxes, and proving your good standing with the state. This number is sometimes confused with the Employer Identification Number (EIN), but they serve completely different purposes. Let’s discuss what makes your Delaware file number so important.
A Delaware state file number (also called the Delaware registration number) is a unique seven-digit identification number that the Delaware Division of Corporations assigns to a business when it is incorporated or formed. Your company file number will appear as a seven-digit number; for example, 1234567. Each new Delaware company will have a state file number one digit higher than the company before it.
For businesses formed in Delaware, this number will serve as their primary state identifier. It’s worth noting that this number cannot be changed, even if your company changes its name, registered agent, directors, or organizational structure. You will only receive a new company file number if you decide to create a brand-new LLC or corporation.

Your Delaware state file number is the primary identifier your business uses when interacting directly with the State of Delaware’s Division of Corporations. It is used almost exclusively for state-level corporate and regulatory compliance.
Delaware state file numbers are generally available to the public via the Delaware Division of Corporations. They maintain a free, public, online database where you can look up any entity registered in the state. The easiest way to do it is to navigate to the official Delaware Division of Corporations Entity Search tool and enter the exact legal name of the business. The search results will display the Delaware file number, the entity name, the entity type, and its current status. Alternatively, a Delaware company name search can also be conducted on our website.
If you’re looking for the state file number of a business outside of Delaware, the process will differ slightly from state to state. Since there is no single national database for all U.S. business registrations, you have to go through the Secretary of State or equivalent agency for the specific state you are interested in.
Business owners regularly confuse these three numbers, but each serves a unique purpose at a different level of government. As discussed, the state file number is issued by the State's Division of Corporations and is used exclusively to maintain your company's legal registration and good standing. The EIN (Employer Identification Number) is a 9-digit number issued by the IRS and is your universal ID for federal tax purposes. Your EIN is often necessary for filing returns, opening bank accounts, and managing payroll. Finally, a State Tax ID (or State Tax Registration Number) is issued by a state's Department of Revenue. You need this number only if you have a state-level tax obligation, such as collecting and remitting state sales tax or paying state unemployment taxes.
Is the Delaware state file number the same as my Tax ID number?
No. These are two different identifiers administered by two different agencies. Your Federal Tax ID Number (EIN) is issued by the IRS and is not tied to any specific state. Your Delaware state file number is issued by the Delaware Division of Corporations and identifies your business in Delaware’s state records.
If my business operates in multiple states, will I need multiple file numbers?
Yes. If you form a Delaware LLC, you’ll receive a Delaware state file number as a unique identifier for your company in that state's records. This number never changes. When your Delaware business starts operating in another state by having a physical presence, employees, or generating substantial revenue there, you must foreign qualify in that state. When this application is approved, the new state will assign your company its own unique identifier for its records. If you operate in more than two states, you will need to repeat this process.
How do I locate my Delaware file number?
The Delaware file number can be located in a few different places. You can find it on the cover letter sent with your approved company documents and on your receipt. The state will stamp it in the margin of your filed Certificate of Formation or Certificate of Incorporation. Furthermore, Harvard Business Services, Inc. can help you with a quick Delaware state file number lookup for your company.
(See an example of a Certificate of Formation below):


*Disclaimer*: Harvard Business Services, Inc. is neither a law firm nor an accounting firm and, even in cases where the author is an attorney, or a tax professional, nothing in this article constitutes legal or tax advice. This article provides general commentary on, and analysis of, the subject addressed. We strongly advise that you consult an attorney or tax professional to receive legal or tax guidance tailored to your specific circumstances. Any action taken or not taken based on this article is at your own risk. If an article cites or provides a link to third-party sources or websites, Harvard Business Services, Inc. is not responsible for and makes no representations regarding such source’s content or accuracy. Opinions expressed in this article do not necessarily reflect those of Harvard Business Services, Inc.
There are 7 comments left for Delaware State File Number: What It Is & How It's Used
Davin. Clegg said: Thursday, July 13, 2017This is Davin Clegg how do i get my filer number for my bank account. Thank you
HBS Staff replied: Tuesday, July 18, 2017If you provide us with your company name, we can give you your Delaware filing number. Feel free to call us at 1-800-345-2677 during normal business hours, Monday - Friday. However, typically the banks do not request the Delaware file number. Banks traditionally need your IRS issued Tax ID Number (EIN).
Mark S. Staniscia said: Tuesday, February 7, 2017How can I find out who the secretary and president of a corporation formed in Delaware in 1970 was any info. appreciated Thanks Mark
HBS Staff replied: Tuesday, February 7, 2017You can try to obtain a copy of the Annual Report from the Delaware Secretary of State.
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