How to fill out Form SS-4

What Form SS-4 is for

Form SS-4 is the IRS application for an Employer Identification Number. An EIN is a nine digit number, written in the format 12-3456789, that identifies a business the way a Social Security number identifies a person. You use it to open a business bank account, hire employees, apply for licenses, and file business tax returns.

You generally need an EIN if your business has employees, operates as a corporation or partnership, files certain excise or employment tax returns, or is a single member LLC that chooses to be taxed as a corporation. Many sole proprietors with no employees can use their own Social Security number instead, but often still get an EIN to keep personal and business identity separate and to avoid handing out their SSN on tax forms.

This is general information, not legal or tax advice. Rules vary by state and province, and the right choice depends on your facts. For anything important, check with a qualified professional.

Before you start

Have a few things ready so you can complete the form in one sitting:

• The legal name of the business and any trade or "doing business as" name.
• The name and Social Security number, Individual Taxpayer Identification Number, or EIN of the responsible party, meaning the person who controls the business.
• The business mailing address and the physical location if it is different.
• The type of entity, such as sole proprietor, partnership, corporation, or LLC.
• The reason you are applying and the date the business started.

Fill out Form SS-4 line by line

1. Line 1, legal name. Enter the exact legal name of the person or entity applying. For a company, this is the name on the formation documents. For a sole proprietor, it is your own full name.
2. Line 2, trade name. If the business operates under a different name than line 1, enter it here. Leave it blank if there is none.
3. Line 3, executor or care of name. Used mainly by estates and trusts, or when a third party should receive mail about the application.
4. Lines 4 and 5, addresses. Enter the mailing address on line 4. If the business street address is different, enter it on line 5.
5. Line 6, county and state. Enter the county and state where the main business is located.
6. Lines 7a and 7b, responsible party. Enter the name and the SSN, ITIN, or EIN of the responsible party. The IRS wants a real person who controls the entity, not a company, in most cases.
7. Lines 8a to 8c, LLC information. If the applicant is a limited liability company, check yes, enter the number of members, and note whether it was organized in the United States.
8. Line 9a, type of entity. Check the box that matches your structure, such as sole proprietor, partnership, or corporation, and give the extra detail requested, like the form number a corporation will file.
9. Line 10, reason for applying. Check the reason, most often "started new business," "hired employees," or "banking purposes."
10. Lines 11 to 13, dates and employees. Enter the date the business started, the closing month of your accounting year (usually December), and the number of employees you expect in the next year.
11. Lines 14 to 17, activity details. Note whether you expect a small employment tax liability, the first date wages were or will be paid, the principal activity of the business, and the products or services it provides.
12. Line 18, prior EIN. State whether the applicant has ever received an EIN before.
13. Third party designee and signature. If someone else may receive the EIN on your behalf, complete the designee section. Then sign, date, and add a daytime phone number at the bottom.

Common mistakes to avoid

• Listing a company as the responsible party. The IRS wants an individual who controls the business in most cases, with their SSN or ITIN.
• Mismatched legal name. The name on line 1 should match your formation documents exactly, or later filings can be rejected.
• Applying more than once. A business needs only one EIN. Applying again creates duplicate records that are hard to untangle.
• Guessing the entity type. The box you check on line 9a affects which returns you must file, so confirm your structure first.

How to file Form SS-4

There are a few ways to submit the application, and the fastest options are usually online or by fax.

• Online. If the responsible party has a valid SSN or ITIN and the business is in the United States or its territories, the IRS online application issues the EIN right away at the end of the session.
• By fax. Send the completed SS-4 to the IRS fax number for your situation. If you include a return fax number, the EIN is typically sent back within a few business days.
• By mail. Mail the form to the address listed in the instructions. This is the slowest route, so allow several weeks.
• By phone. International applicants without a US taxpayer ID can apply by phone using the number in the instructions.

Keep the confirmation notice the IRS sends, called the CP 575, in a safe place. Banks and payers often ask for it to verify your EIN.

SS-4 and the EIN outside the United States

Form SS-4 and the EIN are part of the United States tax system. In Canada, the equivalent identifier is the Business Number issued by the Canada Revenue Agency, and you register for it through the CRA rather than the IRS. If you run a Canadian business that also needs to deal with the IRS, for example because you have US source income or US employees, you may still need a US EIN and would use Form SS-4 for that purpose.

After you get your EIN

Once the EIN is issued, you can use it to open a business bank account, set up payroll, and complete tax forms. A common next step is providing your EIN on a Form W-9 to clients who will pay your business, so they can report those payments. You will also use it on employment forms and information returns at year end.

Do you actually need an EIN?

Not every business is required to have an EIN, so it helps to check before you apply. You generally need one if you have employees, operate as a corporation or partnership, file employment or excise taxes, or have certain retirement plans. A single member LLC with no employees can often use the owner's Social Security number for federal taxes, though many still get an EIN. Even when it is optional, an EIN is useful, because it lets you keep your SSN off forms you hand to clients and vendors, and most banks want one to open a business account. If you are unsure whether your situation requires one, the IRS instructions for Form SS-4 walk through the triggers.

Keep your EIN secure and correct

Your EIN identifies your business on tax filings, so treat it with the same care as any sensitive number. Store the confirmation notice somewhere safe, share the number only with parties that genuinely need it, and use the exact legal name that matches IRS records whenever you provide it. If your business changes in a major way, such as switching from a sole proprietorship to a corporation, you may need a new EIN rather than reusing the old one, because the IRS ties the number to a specific entity type. On the other hand, small changes like a new address or a new trade name usually do not require a new EIN. When you no longer need the number, for example after closing the business, you can ask the IRS to close the business account associated with it, though the EIN itself is never reassigned to another business.

What to do if you lose your EIN

If you misplace your EIN, you do not have to apply again. You can find it on the CP 575 confirmation notice, on a previously filed business tax return, on old 1099 or W-2 forms your business issued, or on bank paperwork where you used it to open an account. If none of those are available, you can call the IRS Business and Specialty Tax Line and, after verifying that you are authorized for the business, they can provide it. Applying for a second EIN when you already have one only creates duplicate records, so always recover the existing number first.

Fill out and store Form SS-4 online

You can complete Form SS-4 on your computer instead of printing and writing by hand. Open our fill a PDF tool, add the SS-4 or any related tax form, type your entries into the correct boxes, and download a clean copy to file or fax. The document is processed in your browser, so your business and personal details stay on your own device.

Related business paperwork is easy to prepare in the same place. Browse the form templates library for company documents, and when a form needs a signature, the sign a PDF tool lets you draw, type, or upload your signature and place it on the page.

Keep every business form in one place

Setting up a business means a stack of forms that you will reuse and update. Create a free account on fillable.ca to save your filled SS-4 and other filings, reuse them next year without starting over, and keep your EIN paperwork organized in one spot.