The Internal Revenue Service (IRS) tracks each taxpayer by a unique individual number which can only be used by that taxpayer. This is true for both individual persons and businesses. As with Social Security Numbers, there are exceptions and regulations as to who needs an EIN number. For more information visit the IRS website.
Who Needs an EIN
If your business structure takes a form other than sole proprietor you are required to have an EIN. If you establish a retirement fund or hire employees, you are required to have an EIN.
Who Doesn't Need an EIN
If you are a registered non-profit organization or agency with the IRS, you do not need an EIN. If you are a church or civic unit you do not need an EIN.
The letters EIN are the shortened name for an Employer Identification Number. This number is issued by the IRS (Internal Revenue Service) to all business which must file tax returns.
An EIN is what a business uses for identification purposes with the IRS. This is similar to an individuals Social Security Number.
If you add or change locations you do not need a new EIN. If you change the business name or type of business, you do not need a new EIN.