What is an EIN?
Understand what an EIN identifies, when the IRS requires one, when a sole proprietor or single-member LLC may not need one, and how to apply directly for free.
Last updated: October 9, 2026
Direct answer
An Employer Identification Number (EIN) is a nine-digit federal taxpayer ID issued by the IRS to identify a business or other entity. The IRS requires an EIN in specified situations, but not every sole proprietor or disregarded single-member LLC needs one for federal income-tax purposes. Banks or state agencies may separately ask for one. Eligible applicants can apply directly through the IRS for free.
What an EIN does—and does not do
An EIN identifies an entity for federal tax administration; it is not an LLC formation document, a state license, or a substitute for every owner's individual taxpayer ID. Rules depend on the entity's federal tax classification and activities, especially employees and certain excise taxes.
The practical distinction
Some businesses need an EIN for federal tax filings. Others obtain one for a bank, state filing, privacy, or client process even when federal tax rules do not require a separate EIN. A single-member LLC that is disregarded for federal income-tax purposes has a specific exception, but employment and certain excise-tax duties can require the LLC's EIN.
When an EIN is used
- 1
Check whether federal rules require an EIN
Common triggers include employees, operating a partnership or corporation, specified excise-tax filings, certain withholding duties, and some entity or ownership changes. Check the IRS rule for your exact classification.
- 2
Do not assume every sole proprietor or single-member LLC needs one
A disregarded single-member LLC without employees or excise-tax liability generally does not need a separate EIN for federal tax purposes. It may still obtain one for banking or state requirements.
- 3
Use the official IRS application if you decide to apply
The EIN itself is free. Eligible domestic applicants can use the IRS online tool; other applicants may need another IRS-approved route.
- 4
Keep the EIN separate from personal tax IDs
An EIN identifies an entity. A person may still need to provide an SSN or ITIN on an individual return or W-9, depending on the entity’s federal classification.
Key takeaways
- An EIN is a federal tax ID for a business or other entity.
- Not every sole proprietor or disregarded single-member LLC needs a separate EIN for federal tax purposes.
- The online application is free for eligible applicants; banks and state rules may separately ask for an EIN.
- An EIN does not create an LLC, provide a license, or authorize work.
Frequently asked questions
Is an EIN the same as a personal tax ID?
No. An EIN identifies a business or other entity. An SSN or ITIN identifies an individual. A disregarded single-member LLC may use the owner’s SSN or EIN for many federal income-tax reporting purposes, while separate employment or excise-tax rules can require the LLC’s EIN.
Is an EIN free?
Yes. The IRS does not charge for an EIN. Apply through IRS.gov; third-party preparers may charge for assistance, but they are not required to obtain the number.
How long does it take to get an EIN?
If an eligible applicant completes the IRS online application and it is approved, the IRS issues the EIN immediately online. Online eligibility is limited; applicants outside the U.S. or without an eligible responsible-party ID may need another route.
Does an EIN expire?
An EIN is not reused or canceled simply because a business closes. The IRS may require a new EIN after certain changes in ownership or structure. Check the IRS rule for the change involved.
Can a sole proprietor get an EIN?
Yes. A sole proprietor may request one even if federal rules do not require it, for example for banking or state purposes. An EIN does not replace the owner’s SSN or ITIN on every individual tax form.
Related guides
Official sources
- IRS: Get an EIN (free official application)
Eligibility for the online tool, application routes, free IRS application, and one-EIN-per-responsible-party daily limit.
- IRS: Employer identification numbers
When an EIN is required, how to apply, and what to do before applying.
- IRS: Single-member LLCs
Federal tax treatment and the EIN exception for a disregarded single-member LLC without employees or excise-tax liability.
Educational information only; not individualized legal, tax, accounting, or financial advice. Rules can change and results depend on your facts. Check current official guidance or consult a qualified professional.