An EIN, or Employer Identification Number, is a nine-digit number the IRS assigns to a business, nonprofit, estate, trust, or similar entity so it can file taxes and meet other federal obligations. It functions as a tax ID for the entity, much like a Social Security number does for an individual. Getting one is free, takes a few minutes online, and is required for most business structures beyond a solo sole proprietor.
What an EIN Is and What It Does
An EIN is formatted as two digits, a hyphen, and seven digits: XX-XXXXXXX (for example, 12-3456789). The IRS uses it to track your entity’s tax accounts, and it appears on every return, deposit, and piece of correspondence you send to federal agencies.1Internal Revenue Service. Publication 1635 – Understanding Your EIN
Outside of taxes, you’ll generally need an EIN to open a business bank account, apply for business licenses, and set up vendor or credit relationships. Sole proprietors who get one can also use it in place of their Social Security number on invoices and W-9 forms, which keeps personal information off business paperwork.
Who Needs an EIN
The IRS requires an EIN in several situations. You need one if any of the following applies to your entity:2Internal Revenue Service. Employer Identification Number3Internal Revenue Service. Businesses With Employees
- You have employees, even one.
- Your business is a corporation or a partnership.
- You run a multi-member LLC, which the IRS treats as a partnership by default.
- You operate a tax-exempt organization, including nonprofits applying for exempt status.
- You administer most estates or trusts. Certain grantor-owned revocable trusts are the exception.
- You withhold tax on income paid to a non-resident alien.
- You file excise tax returns on alcohol, tobacco, firearms, or similar categories.
A sole proprietor with no employees, no excise tax obligations, and no retirement plan can legally use a Social Security number instead. Many still apply for an EIN, because banks, clients, and vendors often ask for one, and it keeps the owner’s SSN off business documents.
How To Apply for an EIN
The IRS issues EINs at no cost. You should never pay a third-party website to get one for you; the FTC has warned about sites charging up to $300 for a service the IRS provides for free.4Internal Revenue Service. Get an Employer Identification Number Apply directly through IRS.gov.
Before you start, have the following ready: your entity’s legal name, its mailing and physical addresses, the entity type (corporation, LLC, partnership, and so on), and the reason you need the EIN. You’ll also need the name and taxpayer ID of the “responsible party,” usually an owner or principal officer, who must provide a Social Security number or ITIN.5Internal Revenue Service. Instructions for Form SS-4 – Application for Employer Identification Number
Apply Online
The IRS online EIN assistant is the fastest option. You answer a short questionnaire and receive your EIN immediately on completion. The tool is available Monday through Friday from 6:00 a.m. to 1:00 a.m. the next day Eastern time, with reduced hours on weekends. You can apply for only one EIN per responsible party per day.4Internal Revenue Service. Get an Employer Identification Number
Apply by Fax or Mail
If you’d rather use paper, download Form SS-4 from IRS.gov. Faxed applications that include a return fax number typically produce an EIN within four business days. Mailed applications take about four weeks.6Taxpayer Advocate Service. Getting an EIN
If You’re Outside the United States
The online tool is not available to applicants without a legal residence, principal place of business, or principal office in the U.S. or its territories. International applicants can call the IRS at 267-941-1099 (not toll-free) to receive an EIN by phone, or fax Form SS-4 to 304-707-9471. If the responsible party has no SSN or ITIN, enter “foreign” or “N/A” on line 7b of Form SS-4.7Internal Revenue Service. Instructions for Form SS-4 (12/2025)
When You Need a New EIN
Changing your business name or mailing address doesn’t require a new EIN. A change in the entity’s legal structure or ownership usually does. The common thread is whether the entity itself has become something different from what it was when the number was first assigned.8Internal Revenue Service. When to Get a New EIN
Common triggers include a sole proprietor incorporating, forming a partnership, or filing for bankruptcy; a corporation receiving a new charter, creating a subsidiary, or merging to form a new corporation (the surviving corporation in a merger keeps its EIN); a partnership incorporating, dissolving and re-forming, or converting to a sole proprietorship; an LLC terminating and re-forming as a different entity type, or a single-member LLC starting to file excise or employment tax returns; a revocable trust becoming irrevocable; and estate funds being used to create a trust.
Updating, Retrieving, or Closing an EIN
When your business address, location, or responsible party changes, file Form 8822-B. Changes in the responsible party must be reported within 60 days. There’s no direct penalty for missing the deadline, but if the IRS doesn’t have your current address, notices of deficiency or demands for payment may never reach you while penalties and interest keep accruing.9Internal Revenue Service. Form 8822-B – Change of Address or Responsible Party – Business
Lost your EIN? Check your original EIN confirmation letter (CP 575), any previously filed return, or your business bank. If none of those work, call the IRS Business and Specialty Tax Line at (800) 829-4933. After verifying your identity, the IRS can look up the number and send a confirmation letter (Letter 147C).2Internal Revenue Service. Employer Identification Number
If you no longer need the EIN, you can ask the IRS to deactivate the associated account, though the number itself is never cancelled and will never be reissued to another entity. First, file all outstanding returns and pay any taxes owed. Then send a letter to the IRS with your entity’s EIN, legal name, address, the EIN assignment notice if you still have it, and your reason for closing the account. Tax-exempt organizations cannot deactivate an EIN if they have applied for exemption, been covered in a group ruling, or filed an information return.10Internal Revenue Service. If You No Longer Need Your EIN