Note the name, telephone number and address of the business for which you want to find the tax ID number.
Register with a website that specializes in federal tax identification look-up, such as FEIN Search, KnowX or FreeERISA. FreeERISA lets you find three tax ID numbers for free but charges for more. The other two websites charge a nominal fee for providing this information.
Pay the fee with a credit card or debit card through the website's payment portal.
Provide the information that the website asks for, such as the company's name, phone number and address.
Click "Submit" to see the business' tax ID number.