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IRS Form SS-4: Applying for an Employer Identification Number


If you run your own business, you need a way to identify it to the government when it comes time to do your taxes. The same is also true if you’re the executor of an estate, the creator of a trust or the founder of a non-profit. The way entities accomplish this is with an Employer Identification Number (EIN). If you don’t yet have an EIN, you can apply to receive one with IRS Form SS-4.

What Is IRS Form SS-4?

Form SS-4 is a form from the Internal Revenue Service (IRS) that you can use to apply for an Employer Identification Number (EIN). An EIN is a nine-digit number that employers, corporations, estates, trusts and other entities use for tax filing purposes. If you have employees or you’re a one-person incorporated business, odds are you have an EIN or you need one.

Who Should Fill Out IRS Form SS-4?

You should fill out IRS Form SS-4 in a wide range of circumstances, including but not limited to:

  • If you’ve started a new business (other than a sole proprietorship)
  • If you’re hiring or plan to hire employees and you don’t yet have an EIN
  • If you’ve changed the legal character of your organization (i.e. you’ve incorporated a sole proprietorship)
  • If you’ve created a pension plan and need an EIN for reporting purposes
  • If you’ve created a trust
  • If you’re administering an estate you need an EIN to complete IRS Form 1041
  • If you’re a single-member LLC or an S corporation and you need an EIN for certain forms like Form 8832 or Form 2553

How to Fill Out IRS Form SS-4

The form can be found on the IRS website. Filling it out is a bit of an involved process, but it’s certainly manageable. There are 18 fields, although not all may be applicable to you. The fields applicable to most people will be the legal name of your business/entity, the trade name if it differs from the legal name, the mailing address, the name of the responsible party, the type of business/entity, the reason for applying, the start date of the business/entity, the principal activity of the business/entity, and if you’ve ever applied for and received an EIN before.

While there are plenty of fields to complete, you shouldn’t have a problem answering anything as long as you have a good understanding of your business, trust or estate. If at any point you aren’t sure how to complete a certain field of the form, the IRS provides line-by-line instructions on its website. From the homepage, just click on Forms & Instructions, then scroll down until you find SS-4.

If you’d rather not deal with the paper form at all, you can also apply for an EIN online on the IRS website. You’ll need a legal residence in the U.S. and a valid Taxpayer Identification Number (your Social Security Number, most likely) to apply online.

How to Submit IRS Form SS-4

You can submit your IRS Form SS-4 by fax or by mail. If you choose to fax in your form, you can send it to the fax number (855) 641-6935. If you choose to mail the form, you can send it to this address:

Internal Revenue Service
Attn: EIN Operation
Cincinnati, OH 45999

If you fax in your form, you can expect to receive your EIN within four business days. Make sure to include your fax number so the IRS can send your EIN back. If you choose to mail, you’ll need to wait roughly four weeks before receiving your EIN.


Bottom Line

An EIN is a crucial piece of identification for employers of all kinds. You’ll also need it if you run a trust or estate. Without one, you won’t be able to file your tax returns correctly, which will lead to further complications down the road. If you enter into any of the many situations in which you’d need an EIN, make sure to complete and submit IRS Form SS-4 well before tax time. That way, you can receive your EIN on time and complete your tax obligations properly.

Tips for Getting Through Tax Season

  • A financial advisor can help you optimize a tax strategy for your business. SmartAsset’s free advisor matching tool can pair you with up to three qualified advisors in your area. Get started today.
  • If you’re a new employer applying for an EIN for the first time, odds are IRS Form SS-4 isn’t the only form you’re going to need to complete. If you’re a charitable non-profit looking for tax-exempt status, for instance, then you’ll need to complete and submit IRS Form 1023.
  • If you’re self-employed and/or run a sole proprietor business, you don’t need an EIN. Still, you’ll have your own tax issues to deal with, including the self-employment tax. And make sure you fill out a W-9 when you start working for another business as a contractor.

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