Need an EIN? Here’s exactly how to file Form SS-4 correctly
You formed your LLC or corporation. The paperwork is filed. Now you try to open a business bank account, and the banker asks for your EIN. You call a payroll service to set up your first employee, and they need your EIN. You start preparing for taxes, and every form asks for your EIN.
If you do not have one yet, getting it is your next step. The good news: the EIN application process is free, takes about fifteen minutes, and you can do it yourself, no paid service required.
Here is everything you need to know about how to get an EIN for your new business using Form SS-4.
An EIN is your business's tax identification number.
An Employer Identification Number is a nine-digit number the IRS assigns to businesses for tax reporting and identification purposes. Think of it as a Social Security number for your company.
The format is XX-XXXXXXX. The first two digits identify the IRS campus that issued the number, followed by seven unique digits. Once assigned, your EIN stays with your business permanently. You do not need to renew it or apply again unless your business structure changes significantly.
The employer identification number serves multiple purposes beyond taxes. Banks require it to open business accounts. Vendors may request it for payment processing. State agencies need it for business licensing and registration. It becomes the identifier that connects all your business activities.
For sole proprietors without employees, using your Social Security number for business purposes is technically allowed. But even then, getting an EIN is usually a good idea. It protects your SSN from unnecessary exposure on invoices, applications, and forms that multiple parties will see.
When you need a new business EIN

Not every situation requires an EIN, but most businesses will need one eventually. These are the most common triggers.
1. You are hiring employees. If you will have anyone on payroll, you need an EIN. The number is required for withholding taxes, filing employment tax returns, and reporting wages. This applies whether you hire one part-time assistant or a team of fifty.
2. You formed a corporation or partnership. These entity types require an EIN regardless of whether they have employees. The IRS treats corporations and partnerships as separate taxpayers, and each needs its own identification number.
3. You want to open a business bank account. Most banks require an EIN to open a business account in a business name. Some may allow sole proprietors to use their SSN, but LLCs and corporations typically need the EIN before the banker will proceed.
4. You are filing certain tax returns. Excise taxes, employment taxes, and certain other filings require an EIN. If your business activities trigger these obligations, you need the number before you can file.
5. You have a Keogh plan or certain trusts. Retirement plans and some trust structures require their own EINs for tax reporting purposes.
6. Your business structure changed. If you converted from a sole proprietorship to an LLC, or from an LLC to a corporation, you may need a new EIN. Changing your business name alone does not require a new EIN, but changing the entity type often does.
How to apply using Form SS-4
Form SS-4 is the official IRS form for applying for an Employer Identification Number. The Form SS-4 guide is more straightforward than it looks. Most of the questions are straightforward if you know your business details.
1. The online application is faster. The IRS offers an online EIN application at irs.gov that provides your number immediately upon completion. The system is available Monday through Friday, 7 AM to 10 PM Eastern time. You answer the questions, submit, and receive your EIN on the screen. The entire process takes about fifteen minutes.
To use the online application, you need a valid Taxpayer Identification Number (your SSN or existing EIN), and the responsible party must have a U.S. address. International applicants must use the phone or mail options.
2. Prepare these details before you start. The SS4 instructions will ask for information you should gather in advance:
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Legal name of the business exactly as registered
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Trade name or DBA if different from the legal name
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Mailing address for IRS correspondence
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The physical address is different from the mailing address
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County and state where the business is located
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Name and SSN of the responsible party (usually the owner or principal officer)
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Type of entity (LLC, corporation, partnership, sole proprietor, etc.)
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Reason for applying (started new business, hired employees, etc.)
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Date the business started or was acquired
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Principal business activity and the specific products or services
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Expected number of employees in the next 12 months
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Expected employment tax liability frequency
The responsible party question trips up some applicants. This should be an individual who controls, manages, or directs the entity. For a single-member LLC, that is you. For a corporation, it is typically a principal officer. The responsible party must have an SSN or ITIN.
3. Alternative methods if online does not work. If you cannot use the online application, you have two other options. You can fax the completed Form SS-4 to the IRS, which typically results in an EIN within four business days. Or you can mail the form, which takes four to six weeks.
Phone applications are also available for international applicants by calling the IRS Business & Specialty Tax Line.
Common mistakes to avoid

The application is straightforward, but a few errors cause problems for new business owners.
1. Using the wrong entity type. Make sure your application matches how your business is actually structured. If you filed as an LLC but select "sole proprietor" on the SS-4, you create a mismatch that complicates future filings.
2. Applying before entity formation is complete. Your business must legally exist before you can get an EIN. If you have not yet received confirmation that your LLC or corporation has been formed in your state, wait until that is finalized.
3. Applying multiple times. If your online application times out or you think something went wrong, do not immediately start over. The IRS may have already assigned an EIN. Check your confirmation or wait for the mail confirmation before applying again. Having multiple EINs for the same entity creates confusion.
4. Using a paid service unnecessarily. Many websites offer to file Form SS-4 for fees ranging from $50 to $300. For most straightforward applications, this is unnecessary. The IRS application is free. Save the money for something your business actually needs.
What to do after receiving your EIN
Once you have your EIN, keep the confirmation notice in a safe place. You will need this number repeatedly for bank accounts, tax filings, state registrations, vendor applications, and more.
If you applied online, print or save the confirmation page immediately. The IRS will also mail a confirmation notice (CP 575) within a few weeks, but having the number right away lets you proceed with other setup tasks.
Update your business records to include the EIN wherever your tax identification is needed. If you have already submitted forms using your SSN, update them to use the EIN going forward.
If you lose your EIN or never received confirmation, you can call the IRS Business & Specialty Tax Line to retrieve it. You will need to verify your identity as the responsible party listed on the application.
The EIN is just the beginning
Getting your new business EIN is one of the first administrative steps in building a legitimate business operation. It takes fifteen minutes, costs nothing, and unlocks the ability to open bank accounts, hire employees, and file taxes properly.
The Form SS-4 guide is not complicated once you understand what information the IRS needs. Gather your details, use the online application, and you will have your number immediately.
From there, the real work of building your business begins. But at least the tax ID is checked off the list.
Suggested Readings
The 4 tax return errors quietly draining service firms before an expert steps in
What your accountant should review every quarter (and what it costs you when they skip it)
Multi-state tax compliance for service firms: What triggers nexus and what to do about it
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