EIN for Corporations-Everything You Should Know

Jan. 19, 2026, 12:15 p.m.
An Employer Identification Number (EIN) is a federal tax ID issued by the IRS. For corporations in the United States, an EIN is not optional—it’s a legal requirement and a core part of doing business. Whether you’re forming a C Corporation or an S Corporation, here’s everything you need to know.
EIN for Corporations-Everything You Should Know

Why Corporations Need an EIN

Every corporation must have an EIN because it is used to:

  • File federal and state tax returns

  • Hire and pay employees

  • Open a business bank account

  • Apply for business licenses and permits

  • Establish business credit

  • Process payroll and benefits

  • Register for sales tax and other state taxes

Even if your corporation has no employees, the IRS still requires an EIN.


When a Corporation Must Get an EIN

You must obtain an EIN if you:

  • Form a new corporation (C-Corp or S-Corp)

  • Convert an LLC or partnership into a corporation

  • Acquire an existing business and operate it as a corporation

  • Create a subsidiary corporation

A corporation cannot legally operate without one.


How to Apply for an EIN

There are three main ways to apply:

  1. Online (Fastest – U.S. only) at https://www.einregister.online/

    • Instant approval

    • Available to applicants with a U.S. SSN or ITIN

  2. By  Phone (502) 547-2551


EIN for C Corporations vs. S Corporations

  • C Corporation:
    Requires an EIN for corporate tax filing and payroll.

  • S Corporation:
    Also requires an EIN.
    Even if you convert from a C-Corp to an S-Corp, the EIN usually stays the same unless the legal entity changes.


Common Mistakes to Avoid

  • Applying before the corporation is legally formed

  • Entering the wrong responsible party information

  • Using a personal SSN instead of the corporation’s EIN

  • Applying multiple times and creating duplicate EINs

  • Using third-party services that overcharge unnecessarily


What Happens If You Lose Your EIN?

You can recover it by:

  • Checking IRS confirmation letters

  • Looking at past tax returns

  • Calling the IRS Business Line

  • Reviewing bank or payroll records

Your EIN never expires.


Final Thoughts

For corporations, an EIN is more than a tax number—it’s your company’s official identity. From banking to hiring, taxes to permits, everything depends on it. Securing your EIN early ensures your corporation can operate legally, professionally, and without delays.

 

EIN for Corporations-Everything You Should Know