How to check a tax id number
Things You'll Need
Apply for your federal tax ID number by filing Form SS-4 online (see Resources). The advantage of filing online is that you will receive your ID as soon as you click the "Submit" button. Alternately, you can print and mail a paper form to the IRS and you will receive your tax ID number by mail in about four weeks. If you apply by phone or fax, you should have your tax ID number in about one week. If you have not received your tax ID number when expected, you can contact the IRS to check the status of your application.
Before contacting the IRS to check the status of your SS-4 application, make sure you have the date of your application and the method of filing. When you file any paperwork with the IRS, you should always make a copy and note the filing date.
To check on the status of your federal tax ID number, contact the IRS by telephone at 800-829-4933. Press the number on your touchtone keypad as directed by the automated recording to have your call directed to "Employee or Federal Identification Number inquiries." The wait on hold can be lengthy, so be patient.
Ask the IRS representative to verify
receipt of your SS-4 application. If the form was received, inquire as to the reason for the delay and provide any additional information requested by the representative. If the application was not received, find out if you need to apply again or if you can provide a copy of your original SS-4. Take the appropriate actions and ask how long you should wait before you follow up again with the IRS.
Wait the specified number of days. If you still don't receive your federal tax ID number in the time specified, repeat the process again, starting with Step 3.
Continue checking the status of your Federal ID Tax Number application so you can provide any additional information the IRS may need to issue your federal tax ID number.
You can start operating your business without a tax ID number, as long as you have the number before you must file tax forms. If you do not have your tax ID number before your first tax filing is due, contact the IRS for special instructions on paying your taxes.
Once you receive your federal tax ID number, you no longer need to contact the IRS for a status report. Be sure to file all required tax forms in a timely manner.Source: ehow.com