The IRS uses employer identification numbers (EINs) to keep track of businesses. An EIN is required if your business:
Has any employees;
Operates as a corporation or partnership;
Has a qualified retirement plan;
Is required to file excise, or alcohol, tobacco, and firearms tax returns; or
Is required to withhold taxes on income (other than wages) paid to a nonresident alien
Note: An EIN is also required for trusts (except certain grantor owned revocable trusts, exempt organization business income tax returns, and IRAs), estates, real estate mortgage investment conduits (REMICs), non-profit organizations, farmers’ cooperatives, and plan administrators.
You can get an EIN by filing Form SS-4 with the IRS, which you can file:
By phone. You should complete the form before calling 1-800-829-4933. When you file by phone, you are given a number for immediate use.
Online. To file online, go to www.irs.gov/businesses, and then click Employer ID Numbers. When you file online, you are given a number for immediate use.
By fax. Complete the form and fax it to the phone number for your area, which can be found on the IRS Web site at www.irs.gov/pub/irs-pdf/iss4.pdf . A faxed request will be processed within four days.
By mail. See the Form SS-4 instructions for the mailing address for your area. A mailed-in request will be processed within four to six weeks.
For more information see IRS Publication 1635, Understanding Your EIN.