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How to Get an EIN in Wisconsin

Last verified: November 10, 2026

An EIN costs nothing and the IRS issues it in minutes online. For a Wisconsin business the part that trips people up is the order: form your LLC or corporation with the Department of Financial Institutions (DFI) first, apply to the IRS second, and register with the Wisconsin Department of Revenue third if you sell taxable goods or services. A sole proprietor with no employees may not need an EIN at all.

Hiring? This page covers the federal number only. Our Wisconsin labor laws and hiring rules for new employers guide picks up from there with the state registrations an employer makes once the EIN is in hand.

Do You Need an EIN?

An EIN is the nine-digit federal tax ID the IRS gives a business. The IRS says you need one if you have employees, if you will pay employment, excise, or alcohol, tobacco and firearms taxes, or if you withhold tax on income other than wages paid to a nonresident alien. You also need one to operate a partnership, an LLC, a corporation, a tax-exempt organization, an estate, a trust or a retirement plan (IRS: employer identification number, read November 10, 2026).

That leaves one group that can skip it: a sole proprietor with no employees and no excise tax filings, who can use a Social Security number. The IRS adds that if you do not need an EIN for federal tax purposes you can still request one for banking or state tax purposes. Our reasoning, not an IRS rule: a Wisconsin freelancer who hands out Forms W-9 to clients may prefer to give an EIN instead of a Social Security number, and that is the best reason for a one-person business to apply.

Spouses Who Own an LLC Together

IRS Publication 555 lists Wisconsin among the nine community property states. IRS Revenue Procedure 2002-69 says the IRS will respect a husband and wife treating an entity they own solely as community property either as a disregarded entity or as a partnership. We read that as relevant to a married Wisconsin couple forming an LLC together, but it is a tax-return choice that a CPA should confirm for your facts. It changes which returns you file, not how you apply for the EIN.

Form Your Wisconsin Entity First

The IRS tells anyone creating an LLC or corporation to form the entity with the state before applying, and warns that an application filed before the state filing may be delayed. In Wisconsin that filing office is DFI, not the Secretary of State. On the DFI fee schedule (Wayback snapshot of October 19, 2026), Articles of Organization for an LLC cost $130 online and Articles of Incorporation for a business corporation cost $100.

The Wisconsin One Stop Business Portal (Wayback snapshot of October 11, 2026) files the DFI registration, the DOR tax registration and the DWD unemployment insurance assessment in a single application. It supports only business corporations, statutory close corporations and LLCs that have not already filed with DFI or registered with DOR. Our Wisconsin LLC guide walks through the DFI filing itself. A sole proprietorship files nothing with DFI first, so go straight to the IRS.

What to Have Ready

The IRS application mirrors Form SS-4, and the Form SS-4 instructions (revision December 2025) say what each line wants. Have these in front of you:

  • Legal name: exactly as it appears on your formation documents. IRS systems accept only letters, numbers, hyphens and ampersands, so spell out symbols, replace slashes with a hyphen and drop apostrophes.
  • Entity type: sole proprietor, partnership, LLC, corporation or another type from the form.
  • Responsible party: the individual who controls the entity and its funds, with a Social Security number or ITIN. It must be a person, not a company, and a nominee cannot apply for you (IRS: responsible parties and nominees).
  • Addresses: a mailing address, plus a physical street address if it differs. The street address line does not take a P.O. box. The IRS allows 35 characters per address line.
  • County and state: the Wisconsin county where the principal business is located.
  • Start date and accounting year: the date the business started or was acquired, and the closing month of your accounting year.
  • Employees: the highest number you expect in the next 12 months.

You do not need a Wisconsin seller's permit number to get an EIN. The permit comes later (see the next section).

Step-by-Step: Getting Your EIN

Step 1: Apply Online With the IRS

The IRS online EIN application is the route we recommend for almost everyone. You can use it if your entity was formed in the United States or its territories, your principal place of business is there too, and you are the responsible party or its authorized representative. If approved, the IRS issues the EIN immediately on screen, with no fee.

  • Finish in one sitting. You cannot save the application, and it expires after 15 minutes of inactivity.
  • You can get only 1 EIN per responsible party per day.
  • The tool runs Monday to Friday 6 a.m. to 1 a.m. Eastern Time, Saturday 6 a.m. to 9 p.m., and Sunday 6 p.m. to midnight. It is not open around the clock. In Wisconsin's Central Time zone the weekday window is 5 a.m. to midnight.

Step 2: Save the Confirmation Letter

Print or save the EIN confirmation letter before you close the page. The IRS says you can use the EIN right away to open a bank account, apply for business licenses or file a tax return by mail. It asks you to wait up to 2 weeks before you e-file a return or make electronic tax deposits. If a return comes due before your EIN arrives, write "Applied For" and the application date where the number goes.

Step 3 (Optional): Apply by Fax or Mail Instead

If you cannot use the online tool, send Form SS-4 to the IRS. The Form SS-4 instructions give one address and one fax number for all 50 states, so a Wisconsin business uses the same ones as everyone else:

  • Fax: 855-641-6935. Include your own fax number and the IRS faxes the EIN back, generally within 4 business days.
  • Mail: Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999. Expect your EIN in the mail in approximately 4 weeks, and allow 4 to 5 weeks before you need it.

The IRS no longer issues EINs by telephone to domestic applicants. Only applicants whose principal place of business is outside the United States can apply by phone, so a service that offers to take a Wisconsin EIN application over the phone is not applying through a domestic IRS phone line.

Common Mistakes With a Wisconsin EIN

  • A name that differs from your DFI filing. Copy the name from your Articles of Organization or Incorporation, then apply the IRS character rules above. Do not shorten it.
  • A P.O. box as the street address. Put the P.O. box on the mailing address line if you use one, and your real workplace or home address on the street address line.
  • Applying twice. The IRS limits online applications to 1 EIN per responsible party per day, and it does not need a new EIN when you only change your business name, address or responsible party. A new one is needed when your structure changes, for example when a sole proprietor incorporates or forms a partnership, or when a single-member LLC has to file employment or excise taxes (IRS: when to get a new EIN).
  • Naming a company or a nominee as responsible party. The IRS says the responsible party must be a person who controls the entity, and that nominees are not authorized to apply.
  • Not writing the number down. If you close the online page without saving the letter, you can still confirm your EIN with the IRS. The IRS EIN page lists the ways to confirm a number.

Wisconsin Steps After the EIN

The EIN is a federal number. The state steps that follow depend on what you sell and whether you hire.

Is an EIN Really Free?

Yes. The IRS page says "You never have to pay a fee for an EIN" and warns about websites that charge for one. A formation service that bundles an EIN with a state filing is a convenience you can choose, but the IRS application itself costs nothing and takes minutes.

Disclaimer

This article is general information, not legal, accounting or tax advice. EIN rules come from the IRS pages and Form SS-4 instructions named in the Sources list below, read on November 10, 2026, and they can change. For questions about your own structure, talk to a CPA or tax attorney. The Wisconsin Small Business Development Center offers no-cost, confidential consulting, and the U.S. Small Business Administration Wisconsin District Office serves the whole state.

Sources

Keep exploring: related Wisconsin guides