EIN for S Corp: Application, Form 2553 Timing, and Updates

Getting an EIN for an S corp is free, takes about 15 minutes through the IRS online application, and the number is issued on screen as soon as you finish. You can also submit Form SS-4 by fax or mail if the online tool isn’t an option. Once you have the EIN, you can file Form 2553 to elect S corporation status, open a business bank account, and file the corporation’s Form 1120-S.¹

What to Have Ready Before You Apply

The online application is an electronic version of Form SS-4, so the information you’ll enter is the same either way. Pull these together first:

The corporation’s full legal name and address, exactly as they appear on the Articles of Incorporation filed with your state. Any mismatch will cause delays or a rejection.
The name and Social Security Number (or ITIN) of the responsible party, meaning the individual who controls the corporation and directs its funds. For a single-shareholder S corp, that’s the owner. This goes on Lines 7a and 7b of Form SS-4.²
Entity type. On Line 9a, check “Corporation” and enter 1120-S as the return you plan to file.²
A reason for applying. “Started New Business” fits most new corporations.
The business start date and the closing month of your accounting year.
The number of employees you expect to hire in the next 12 months.

If you want an attorney or accountant to receive the EIN on your behalf, you can name a third-party designee on the form. That authorization ends the moment the IRS releases the EIN to them.³

Applying Online at IRS.gov

The online EIN Assistant at irs.gov is the fastest route. It walks you through the SS-4 questions and issues the EIN on screen when you finish, usually in about 15 minutes.

Two conditions apply: the responsible party must have a valid SSN or ITIN, and the corporation must be a domestic entity. The tool is available Monday through Friday from 6:00 a.m. to 1:00 a.m. Eastern Time, Saturday from 6:00 a.m. to 9:00 p.m., and Sunday from 6:00 p.m. to midnight. The IRS limits the tool to one EIN per responsible party per day, so if you’re forming multiple entities, plan for separate days.¹

When the EIN appears, download and print the CP 575 notice right away. This is the corporation’s official proof of EIN assignment, and the IRS issues it only once. Lose it and the IRS will not send a duplicate. You would have to call the Business and Specialty Tax Line at 1-800-829-4933 and request a 147C verification letter as a replacement. Keep the CP 575 with your Articles of Incorporation and bylaws in the corporation’s permanent records.

Applying by Fax or Mail

If the responsible party doesn’t have an SSN or ITIN, which is common for foreign individuals, you can’t use the online tool. You’ll need to submit a paper Form SS-4 by fax or mail, signed by the responsible party or an authorized representative.

Fax is the faster paper option. The IRS Fax-TIN service runs 24 hours a day, seven days a week, and the EIN is generally faxed back within four business days.⁴ Include your return fax number on the form.

Mailing the form takes roughly four weeks. Both fax and mail submissions go to an IRS office based on the applicant’s location, so check the SS-4 instructions for the correct number and address for your state. Incomplete or illegible forms get returned, so review every field before sending.

Get the EIN Before You File Form 2553

The order matters. The EIN has to be on hand before you file Form 2553, the form that elects S corporation treatment. Your EIN goes on the first page of that form.⁵

The election is due no later than two months and 15 days after the beginning of the tax year you want it to take effect. You can also file it at any time during the preceding tax year.⁶ Miss that window and the election is pushed to the following tax year, which means the corporation is taxed as a C corp in the interim. That’s why the online application is worth using when you can: waiting four weeks for a mailed EIN can eat most of your filing window.

When You Don’t Need a New EIN

Not every S corp filer needs a fresh EIN. The IRS treats some situations as the same entity continuing under a different tax classification:⁷

A sole proprietor incorporating for the first time needs a new EIN. The legal entity has changed from an individual to a corporation.
An LLC electing to be taxed as an S corp does not need a new EIN. The IRS views this as the same entity changing its tax classification.
An existing corporation electing S corp status does not need a new EIN. Choosing S corp taxation doesn’t change the underlying corporate entity.
A new corporation formed by merger needs a new EIN for the new entity.

Changing the corporation’s name or moving its principal office also does not trigger a new EIN. Those are updates to the existing record.⁷

Keeping the EIN Record Current

After the EIN is assigned, the IRS expects you to report certain changes. If the responsible party changes, file Form 8822-B within 60 days. There’s no penalty for filing it late, but the practical consequences are real: the IRS may send deficiency notices and demand letters to the old responsible party at an outdated address, and penalties and interest continue accruing whether the notices reach anyone or not.⁸

For a corporate name change, check the “Name Change” box on the next Form 1120-S you file. No new EIN is required.

Skip the Paid EIN Websites

Applying for an EIN through the IRS costs nothing. The IRS states plainly: “You never have to pay a fee for an EIN.”¹ Still, plenty of sites styled to look official charge $50 to $300 to file the same free application on your behalf. Some use IRS logos, mimic IRS formatting, and put “IRS” in their domain names. The only legitimate site for the online application is irs.gov.

Paid incorporation services and attorneys sometimes bundle the EIN application into a broader formation package, and that’s a different situation: you’re paying for the whole service. But if a standalone website’s only product is filing an EIN application, you’re paying for something the IRS will do for free in about 15 minutes.

1
Internal Revenue Service. Get an Employer Identification Number
2
Internal Revenue Service. Form SS-4 (Rev. December 2025)
3
Internal Revenue Service. Instructions for Form SS-4 (Rev. December 2025)
4
Internal Revenue Service. Instructions for Form SS-4 (Rev. December 2025)
5
Internal Revenue Service. IRS Form 2553 – Election by a Small Business Corporation
6
Internal Revenue Service. Instructions for Form 2553
7
Internal Revenue Service. When to Get a New EIN
8
Internal Revenue Service. Form 8822-B, Change of Address or Responsible Party — Business