An EIN — Employer Identification Number — is a unique nine-digit number issued by the IRS to identify a business entity for tax purposes, much like a Social Security Number identifies an individual. You may need an EIN to hire employees, open a business bank account, file business tax returns, or apply for business licenses. The IRS issues EINs free of charge, and you can typically receive one in minutes by applying online through the IRS EIN Online Assistant. This guide explains who needs an EIN, how to apply, and what to do once you have one.
What Is an EIN?
An EIN, also called a Federal Tax Identification Number (FTIN), is a nine-digit number formatted as XX-XXXXXXX that the IRS assigns to businesses, estates, trusts, nonprofit organizations, and other legal entities operating in the United States. The IRS uses your EIN to track your entity's tax filings and payments. Each legal entity typically receives its own EIN — for example, if you operate two separate LLCs, each may need its own number. Sole proprietors with no employees may use their SSN instead, though many choose to obtain an EIN for privacy reasons and to protect their business identity.
Who Needs an EIN?
The IRS requires an EIN if your business has employees, operates as a corporation or partnership, files certain excise tax returns, withholds taxes on income other than wages paid to a non-resident alien, or has a Keogh plan. Beyond IRS requirements, most banks require an EIN to open a business checking or savings account, even for sole proprietors. Many states also require an EIN when applying for a business license or registering a trade name. If you operate any legal business structure other than a sole proprietorship with no employees, you will almost certainly need an EIN.
Common Entities That Require an EIN
Entities that typically require an EIN include sole proprietors with employees, single-member LLCs that have employees or elect corporate tax treatment, multi-member LLCs, S corporations, C corporations, partnerships, estates of deceased individuals, trusts, and nonprofit organizations. Even if your entity does not legally require an EIN, obtaining one keeps your SSN off business documents and helps protect against identity theft. Consult a CPA or tax attorney if you are unsure whether your specific structure requires an EIN.
How to Apply for an EIN
The IRS offers four ways to apply for an EIN: online, by fax, by mail, and by phone for international applicants. Online is the fastest and most convenient method — you receive your EIN immediately upon completing the IRS EIN Online Assistant at irs.gov. The online tool is available Monday through Friday, 7 a.m. to 10 p.m. Eastern Time. All application methods are free; never pay a third-party service to obtain an EIN on your behalf, as the IRS does not charge for this service.
Step-by-Step: Applying Online
Go to irs.gov and search for "EIN Online Assistant" or navigate directly to the EIN application page. Select the type of legal entity that applies to your business (sole proprietor, LLC, corporation, partnership, estate, trust, etc.). Answer the interview-style questions about your entity, including your legal name, address, and reason for applying. Once you submit, the IRS immediately issues your EIN — print or save the confirmation page, as the IRS will not send a separate confirmation letter for online applications.
Applying by Fax or Mail
If you cannot complete the online application, you may submit IRS Form SS-4 (Application for Employer Identification Number) by fax or mail. Fax applications typically take about four business days to process; mail applications may take four to five weeks. Download Form SS-4 for free from irs.gov. Provide complete and accurate information to avoid delays — the IRS may contact you if the form is incomplete. Understanding how many calendar days 3–5 business days covers helps you set expectations.
What to Do After You Receive Your EIN
Once you have your EIN, use it to open a business bank account, apply for business licenses, set up payroll, and file your first business tax return. Keep your EIN in a secure location — you will use it repeatedly on tax documents and when working with banks and government agencies. If you lose your EIN, you can call the IRS Business & Specialty Tax Line at 800-829-4933 to retrieve it. Your EIN does not expire, but certain changes to your business structure — such as changing entity type — may require you to obtain a new one. Understanding how tax write-offs work for your business expenses becomes important once you have your EIN in place, and learning how to reconcile in QuickBooks Online helps you keep your books accurate for tax filing.
EIN vs. SSN: Key Differences
Your Social Security Number (SSN) identifies you as an individual to the IRS and Social Security Administration, while an EIN identifies your business entity. Using an EIN for business activities instead of your personal SSN reduces the risk of SSN-related identity theft on business forms and invoices. Sole proprietors without employees are not required to have an EIN, but many choose to get one specifically to avoid putting their SSN on documents shared with vendors and clients. The two numbers are not interchangeable — use each only for its intended purpose. If you have employees, your EIN is also required for payroll processing — see the 2026 biweekly pay schedule for payroll planning. Filing accurate returns under your EIN reduces the chance of an IRS audit.
Frequently Asked Questions
How much does it cost to get an EIN?
Getting an EIN from the IRS is completely free — the IRS does not charge any fee to issue an Employer Identification Number. Be cautious of third-party websites that charge a fee to apply on your behalf; these services are unnecessary since you can apply directly at irs.gov in minutes. Always apply through the official IRS website or by submitting Form SS-4 directly to the IRS.
How long does it take to get an EIN?
If you apply online through the IRS EIN Online Assistant, you receive your EIN immediately upon completing the application — the process typically takes less than 15 minutes. Fax applications typically take about four business days. Mail applications may take four to five weeks. The online method is strongly recommended if you need your EIN quickly to open a bank account or start hiring.
Can a sole proprietor get an EIN?
Yes — sole proprietors may apply for an EIN even if they are not required to have one, and many do so to avoid using their SSN on business documents. You are required to have an EIN as a sole proprietor if you have employees, have a Keogh retirement plan, or file certain excise tax returns. The IRS EIN Online Assistant accepts sole proprietor applications through the same process as other entity types. If you are starting a business with limited capital, an EIN is often one of the first free steps you can take.
Do I need a new EIN if I change my business structure?
You may need a new EIN if you change your business structure — for example, converting from a sole proprietorship to a corporation or partnership typically requires a new EIN. Simply changing your business name or address does not require a new EIN, though you should notify the IRS of the change. Consult the IRS guidance at irs.gov or a qualified CPA to determine whether your specific structural change triggers the need for a new number.
What if I lose my EIN?
If you lose your EIN, call the IRS Business & Specialty Tax Line at 800-829-4933 — an IRS representative can look up your number after verifying your identity. You may also find your EIN on previously filed tax returns, bank account documents, or IRS correspondence. One useful resource is the IRS transcript of your previously filed returns, which will include your EIN. The IRS will not reissue EINs; it will only retrieve the existing one associated with your entity.
Sources & References
- IRS — Employer ID Numbers — https://www.irs.gov/businesses/small-businesses-self-employed/employer-id-numbers
- IRS — Form SS-4: Application for Employer Identification Number — https://www.irs.gov/forms-pubs/about-form-ss-4
- IRS — Do You Need a New EIN? — https://www.irs.gov/businesses/small-businesses-self-employed/do-you-need-a-new-ein
Last updated: April 28, 2026