Key takeaways IRS Form SS-4 is used to obtain an Employer Identification Number (EIN) for your business or other entity such as a trust or estate. The SS-4 form requires detailed information about ...

Mail applications take the longest. The IRS says businesses should expect to receive an EIN four to five weeks after ...

You can either apply by fax, mail or online. If you apply by fax or mail, you must fill out and submit the IRS Form SS-4. If you need your EIN number fast, you can apply online.

When you hire employees, you must get an employer identification number (EIN) to use on tax returns and other documents you submit to the IRS. To get an EIN, you must file IRS Form SS-4.