An employer identification number (EIN) is a unique nine-digit business tax ID the IRS uses to identify a business for tax and reporting purposes — essentially a Social Security number for a business.
At a glance
- An EIN is a tax ID number for businesses.
- Some businesses are required to have one; all business types can apply for one.
- Applying is free and can be done online through the IRS website.
Who needs an EIN
The IRS requires an EIN for corporations, partnerships, and LLCs. Any business type, including sole proprietorships, can apply even if not required. An EIN is required if the business:
- Currently has or plans to hire employees
- Operates as a corporation or partnership
- Withholds taxes on income paid to nonresident aliens
- Has a solo 401(k) or other self-employed retirement plan (sometimes called a Keogh plan)
- Was bought or inherited
- Files Employment, Excise, or Alcohol, Tobacco and Firearms tax returns
Trusts, estates, and non-profits also generally require an EIN.
Cost and how to apply
The application is free. File Form SS-4, Application for Employer Identification Number, using one of these methods:
- Online: Complete the application in a single session on the IRS website; the EIN is issued immediately once the system accepts the submission.
- Mail or fax: Print, complete, and mail or fax Form SS-4 to the IRS.
- Phone: International applicants can call 267-941-1099 (not toll-free), 6 a.m.–11 p.m. ET, Monday through Friday.
Benefits of getting an EIN
- Legal separation: Separates business finances from personal affairs, providing liability protection and simplifying finances.
- Business bank account: Many banks require an EIN to open a business account, even for sole proprietors; a business account also helps when applying for loans or credit lines.
- Avoiding identity theft: Using an EIN instead of a personal Social Security number reduces exposure of the SSN for business purposes.
- Building business credit: Credit applied for under an EIN shows up on the business credit report, contributing to a business credit score and easing future financing.
Changing an EIN
An EIN is meant to be permanent and generally can’t be changed on a whim. A new EIN may be required if business ownership or structure changes. The IRS maintains guidance on which structure changes require a new EIN.
FAQs
How do I look up my EIN? Check IRS documents such as the EIN confirmation letter (CP-575), past tax returns, or business bank paperwork. If unavailable, call the IRS Business & Specialty Tax Line at 800-829-4933 and be ready to verify identity.
What is an EIN used for? Filing business tax returns, opening a business bank account, hiring employees, applying for licenses, and separating business finances from personal taxes.
Can I look up another business’s EIN? Generally no — it’s considered sensitive information. It may appear on public documents like SEC filings (public companies) or Form 990 (nonprofits), or can be requested directly from the business.
How do I cancel an EIN? An EIN can’t technically be canceled, but the IRS account can be closed. Send a letter with the business name, EIN, business address, and reason for closing (attaching a copy of the EIN Assignment Notice if possible) to: Internal Revenue Service, Cincinnati, OH 45999. Pay any outstanding tax and file the final business return before closing. Once closed, the EIN is never reused and remains permanently tied to that business.
This article is for informational purposes only and not legal or financial advice.