When you run your own business, you must pay yearly taxes. Some of these are federal, some are state and, depending on your business and location, some are local. In all cases, you must register with the Internal Revenue Service as well as with state and relevant local tax agencies in order to get your tax Id number [source: SBA].

Here are some of the ways you can get a federal tax Id number -- also known as an Employer Identification Number (EIN) -- for your business:

  • Online The best and fastest way to get your tax Id number is to apply online. Go to the Internal Revenue Service Web site at http://www.irs.gov/businesses/small/article/0,,id=102767,00.html, and read the information posted there. Then click APPLY ONLINE NOW. Please note that the application is only available at the indicated hours. Also, you can only apply online if your business is located in the United States or its territories.
  • Toll-free phone service Call the Business and Specialty Tax Line on their toll-free number. If you're calling from outside the United States, there is no toll-free number.
  • Fax Download Form SS-4 from http://www.irs.gov/pub/irs-pdf/fss4.pdf, fill it out and fax it in to the appropriate office. Be sure to include your fax number, so you can have your tax Id number faxed to you, otherwise, your tax Id number will be mailed to you.
  • Mail This is the slowest method, and it can take up to four weeks to receive your tax Id number if you mail in the form. Download Form SS-4 from http://www.irs.gov/pub/irs-pdf/fss4.pdf and fill it out. Mail your form to the appropriate office [source: IRS].