IRS Form SS-4 Online – Fast EIN Application for US Businesses

IRS Form SS-4 Online – Starting a business in the United States requires several key steps, and obtaining an Employer Identification Number (EIN) is one of the most essential. The IRS Form SS-4 provides a straightforward way to apply for this number, especially through the online process, which offers a fast and efficient application for US businesses. Whether you’re a sole proprietor, LLC, corporation, or partnership, understanding how to use IRS Form SS-4 online can save you time and ensure compliance with tax regulations. In this guide, we’ll cover everything you need to know about the EIN application process in 2026.

What Is an EIN and Why Do US Businesses Need One?

An Employer Identification Number (EIN) is a unique nine-digit identifier assigned by the Internal Revenue Service (IRS) to businesses for tax purposes. It’s similar to a Social Security Number but for entities like corporations, partnerships, sole proprietors, estates, trusts, and nonprofits. Businesses need an EIN to file taxes, open bank accounts, hire employees, and comply with IRS withholding regulations.

Without an EIN, you can’t legally operate certain aspects of your business, such as paying wages or applying for business licenses. Even if you’re a sole proprietor without employees, an EIN is often required for banking and credit applications.

Understanding IRS Form SS-4: The Application for Employer Identification Number

IRS Form SS-4, officially titled “Application for Employer Identification Number,” is the document used to request an EIN. Revised as of December 2025, it collects details about your business entity, responsible party, and operations. The form includes sections for legal name, address, entity type, reason for applying, and principal activity.

Key updates in the 2025 revision include adjustments to Line 14 for employment tax liability thresholds, such as $6,536 or less in wages for employers in U.S. territories electing Form 944. Businesses must keep Form SS-4 information current and report changes using Form 8822-B within 60 days.

Eligibility Requirements for Online EIN Application Using Form SS-4

Not every applicant can use the online EIN application. To qualify:

  • Your principal place of business must be in the U.S. or U.S. territories.
  • The applicant must be the responsible party (e.g., owner or authorized representative) with a valid Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or EIN (for government entities only).
  • Third-party designees need signed authorization.
  • International applicants or those without a U.S. principal business location must use phone, fax, or mail.

There’s a daily limit: only one EIN per responsible party per day.

Benefits of Applying for EIN Online

Applying for an EIN online via IRS Form SS-4 is the fastest method for eligible US businesses. Key advantages include:

  • Immediate Issuance: Receive your EIN instantly upon approval, as a downloadable PDF confirmation notice.
  • Free Service: No fees from the IRS—avoid third-party sites that charge.
  • Convenience: Complete the application in one session from anywhere with internet access.
  • Efficiency: No waiting for mail or fax responses, which can take weeks.

This method is available Monday–Friday from 6:00 a.m. to 1:00 a.m. ET (next day), Saturdays 6:00 a.m.–9:00 p.m. ET, and Sundays 6:00 p.m.–12:00 a.m. ET.

Step-by-Step Guide to the Online EIN Application Process

Follow these steps for a fast EIN application:

  1. Prepare Your Information: Gather details like business name, address, entity type, responsible party’s SSN/ITIN, and reason for applying.
  2. Visit the IRS Website: Go to the official EIN application page at IRS.gov.
  3. Complete the Interview-Style Form: Answer questions based on Form SS-4. The session must be finished in one go—no saving drafts. It expires after 15 minutes of inactivity.
  4. Submit and Review: Double-check for accuracy and submit. If approved, your EIN appears immediately.
  5. Download Confirmation: Print and save the CP 575 notice for records.

For new entities like LLCs, form the business with your state first to avoid delays.

Required Information for IRS Form SS-4 Online

To complete the application, you’ll need:

  • Legal name and trade name of the business.
  • Mailing and physical addresses.
  • Responsible party’s name and SSN/ITIN/EIN.
  • Entity type (e.g., sole proprietor, corporation).
  • Number of LLC members (if applicable).
  • Date business started or acquired.
  • Expected number of employees.
  • Principal business activity and line of merchandise/services.
  • Reason for applying (e.g., new business, hired employees).

If using a third-party designee, include their contact details and authorization.

Processing Time and Confirmation for Online Applications

Online applications provide instant EIN issuance if everything is correct. You’ll receive a digital confirmation letter (CP 575) to download and print. For fax or mail submissions using paper Form SS-4, expect:

  • Fax: About 4 business days.
  • Mail: 4–5 weeks.

As of February 2026, the IRS is processing paper Form SS-4 applications from December 2025.

Common Mistakes to Avoid When Applying for EIN Online

  • Inactivity Timeout: Have all info ready to avoid restarting.
  • Incorrect Entity Type: Select the right box to prevent rejection.
  • Multiple Applications: Use only one method per entity.
  • Outdated Form: Always use the latest version from IRS.gov.
  • Missing Authorization: For third parties, ensure signed consent.

Double-check for accuracy to ensure a smooth process.

Alternatives to Online EIN Application

If you’re ineligible for online:

  • Phone (International Only): Call +1-267-941-1099 (6:00 a.m.–11:00 p.m. ET) for immediate EIN.
  • Fax: Send to 855-641-6935; receive in 4 days.
  • Mail: Send to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999; wait 4–5 weeks.

International applicants use specific fax/mail addresses from Form SS-4 instructions.

Frequently Asked Questions About IRS Form SS-4 and EIN Applications

How much does it cost to apply for an EIN?

It’s free directly from the IRS. Beware of paid services.

Can I apply for an EIN without a Social Security Number?

No, the responsible party needs an SSN, ITIN, or EIN (for governments).

What if I lose my EIN confirmation?

Request a replacement by calling the IRS Business & Specialty Tax Line at 800-829-4933.

Do sole proprietors need an EIN?

Not always, but it’s recommended for banking and privacy.

Has Form SS-4 changed in 2026?

No major changes; the December 2025 revision remains current.

Applying for an EIN using IRS Form SS-4 online is a quick, free way for US businesses to get started. With immediate results and easy access, it’s the best option for most applicants. Always use official IRS resources to avoid scams and ensure accuracy. If you’re ready to apply, head to IRS.gov today and secure your EIN in minutes.