LetterAgent
Mail physical letters by just asking your AI assistant.
Yes: mail a completed Form SS-4 to the IRS, and it will assign your Employer Identification Number in approximately four weeks. Mail is the right route when you can't use the online application, which requires a Social Security number or ITIN. Need it faster? Fax the form with a return fax number and the IRS typically sends the EIN back in about four business days.
This is general information, not tax advice.
Mail the completed Form SS-4 to: Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999. That's it: one form, one envelope. Use the current version of the form from irs.gov, fill it out completely, and sign it. An incomplete or unsigned form gets sent back, and the clock restarts.
| Route | Timing | Best for |
|---|---|---|
| Online at irs.gov | Immediate, during posted hours | Applicants whose responsible party has a Social Security number or ITIN |
| Fax the SS-4 | About four business days, with a return fax number included | Anyone who can't use the online tool but wants the number soon |
| Mail the SS-4 | Approximately four weeks | Anyone, especially with no fax access and no deadline pressure |
Two facts that save people money and trouble: the EIN itself is always free from the IRS, so never pay a third-party site for one, and the IRS limits issuance to one EIN per responsible party per day, whichever route you use. International applicants, whose principal place of business is outside the US, use a separate phone, fax, and mail path: follow the international section of the IRS EIN page rather than guessing at numbers.
Errors. A mismatched responsible-party name, the wrong entity type, or an unsigned form sends the application back and restarts the wait. Form your entity with your state first if you're creating an LLC or corporation: the IRS warns that skipping this step delays the application. And mind the form's character rules: the IRS only accepts letters, numbers, hyphens, and ampersands in business names, so spell out symbols and drop apostrophes. If a tax return comes due while you're waiting, write "Applied For" and the application date in the EIN space instead of using your Social Security number there.
One honest note: LetterAgent prints and mails letters to US and Canadian addresses, but the SS-4 application, with its signatures and entity details, is yours to complete. LetterAgent doesn't file tax forms: it can only put your finished, signed form in the mail.
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is printed and mailed.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
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