An Employer Identification Number, or EIN, is a nine-digit number the IRS assigns to identify a business for tax purposes. Despite the name, you may need one even if you do not have employees.

When a business needs an EIN

The IRS Employer ID Numbers page explains who needs one. In general, businesses that have employees, operate as a corporation or partnership, or file certain tax returns need an EIN. Many single-owner businesses also get one so they can open business bank accounts and avoid giving their Social Security number to clients on Form W-9. The IRS page includes a set of questions to help you decide.

Apply free, directly with the IRS

The IRS states that you can get an EIN for free directly from the IRS, and that applying online can take minutes. Be cautious with websites that charge a fee to obtain an EIN for you; they are not the IRS, and you do not need them. The IRS also notes that you can apply for only one EIN per day, whether online, by phone, mail or fax.

What you need before applying

  • The legal name of the business and any trade name
  • The type of entity, such as sole proprietor, LLC, partnership or corporation
  • The responsible party's name and taxpayer identification number
  • The business address and start date
  • The main activity of the business

Choosing the entity type comes first. The IRS explains the options on its business structures page, and our guide to business structure tax considerations covers how they are taxed.

After you receive it

  • Keep the IRS confirmation notice with your permanent records
  • Use the EIN on business bank applications, payroll registrations and W-9 forms
  • Register with your state revenue agency where required; our state guides link to official sites
  • If you will have employees, set up payroll and review understanding employment taxes

Lost your EIN?

The IRS page explains ways to find a lost EIN, such as checking the confirmation notice, old returns or bank records, and how to request verification from the IRS.

Changes to the business

Some changes, such as changing the entity type, may require a new EIN, while others, such as a name change, generally do not. The IRS EIN pages explain which changes require a new number.

Key terms

  • EIN: Employer Identification Number, the nine-digit number the IRS uses to identify a business.
  • Responsible party: the person who ultimately owns or controls the entity, whose details are given on the application.
  • Entity type: the legal and tax form of the business, such as sole proprietorship, partnership, LLC or corporation.
  • Confirmation notice: the IRS notice issued when an EIN is assigned. Keep it with permanent business records.
  • TIN: taxpayer identification number, a general term that includes EINs and Social Security numbers.

Keep your EIN confirmation, formation documents and bank account details together in one permanent folder.

Starting out

The IRS also has a starting a business page that lists other early steps. If you would like help setting up books, payroll and tax records from day one, see our bookkeeping services or book a consultation.