Every business required to file taxes in the United States must have an Employer Identification Number. An EIN is issued by the Internal Revenue Service to businesses upon receipt of an EIN application. You may need to find a business's EIN to report payments sent to or received from a particular business, or you may need an employer's EIN to fill in your 1040 form. Whatever reason you have to find the number, there are plenty of resources where you can find EINs for free.
Navigate to the Guidestar website listed in Resources. The Guidestar website allows you to search for a nonprofit organization's EIN for free. The EIN is, in most cases, listed on the front page of IRS form 990.
Go to the U.S. Security and Exchange Commission's EDGAR database using the link in Resources. Click on the "Search for Filings" link to access the agency's database. EINs are on the first page of many SEC-mandated filings for public companies, including 10-Ks.
Check with your local public library to ask a reference librarian what databases the library have access too. Many for-fee databases, like Lexis and ReferenceUSA, are available at public libraries for free public use.
Contact the IRS with your request. Include as many details as you can about the business and your reason for the request. Expect to wait four to six weeks for a response. The request should be mailed to the same IRS office you send your tax return to. If you are unsure about the address, call the IRS at 800-829-1040 and ask for that information.