Applying for a taxpayer identification number step-by-step

You need a taxpayer identification number, also known as a TIN, to be able to identify yourself to the IRS. The number is unique to you and has 9 digits. Who needs a TIN? How do you get one? Why are there different kinds? The answers to these questions are readily available, and getting your SSN or EIN is only a few steps away.

Who needs a TIN?

In short, anyone who deals with the IRS needs a taxpayer identification number. It’s required on your tax returns and other tax-related documents. It may be requested by the IRS in other interactions you have with them, both to help the IRS keep track of you and for you to get relevant information if you need help from the IRS. This means that you must have a taxpayer identification number of some kind, and depending on which kind of taxpayer identification number you need for corresponding with the IRS, you may need to apply for a TIN.

The types of taxpayer identification numbers in the United States vary from Social Security Numbers, which each US Citizen has, to ATINs, which are temporary numbers required in the special case of adopting a child. It may be that you already know which TIN you need, and already have it, but you don’t remember what it is or where you can find it. In this case, our article on how to find out your TIN will help you get the information you need.

Types of TIN

Unfortunately, a taxpayer identification number is not a one-size-fits-all piece of documentation. This would make little sense anyway, because the number is used to identify your unique situation to the IRS. If you’re employed at a company, your tax responsibilities are not the same as someone who is an employer. Similarly, if you are a US citizen or not, your taxpayer identification number will be different. Applying for the right TIN is therefore only possible if you know which one you need. These sections will help you find out how to apply for each, but to help you jump right in to the correct one, here is a summary of what each number is, and who should apply for one:

  • SSN: This is the social security number that each US citizen has to apply for to get a credit card or, as the name suggests, social security.
  • EIN: An Employer Identification Number or EIN is the number you get as an employer or as a business.
  • ITIN: An ITIN is the number you get if you are required to have a TIN, but you do not have an SSN.

Social Security Number

Your social security number, often abbreviated to SSN, is a number you get from the Social Security Administration (SSA), and is issued only once (meaning that this number will never change throughout your lifetime (you can apply for a replacement SSN card if you misplace it). The SSA has offices throughout the US, and you will most likely be able to visit an office in any major area.

However, you do not necessarily need to show up in person to receive your SSN. If you require a replacement TIN, you can get your SSN online. This can be done at the SSA’s website, but please bear in mind that the following states are currently excluded from this scheme: Alabama, Connecticut, Minnesota, Nevada, New Hampshire, Ohio, Oklahoma, Orego,n Utah, and West Virginia. You’ll need a mySocialSecurity account.

To apply for your social security number, you need to visit one of the offices of the SSA. Bring with you your passport, eligibility documents (work permit, for example), and the filled out form SS-5. You’ll also need to provide a valid e-mail address, so you can receive the physical SSN card which will be posted to you. This happens a few weeks after your application has been approved.

Once your SSN card arrives, you might notice a few restrictions printed on it. If you do not understand these, you can contact the SSA on their toll-free number at 1-800-772-1213.


It could be that you used to have an ITIN before you were eligible for an SSN. Once you make a successful application for an SSN, you should make sure you rescind your ITIN to avoid confusion.

Employer Identification Number (EIN)

You’ll need an Employer Identification Number or EIN if you run a business that has employees, for example. You will also need one if your legal structure is a corporation or partnership. However, this business must be in the US, or be in a US territory. EINs cannot be applied for by legal entities other than individuals, that is to say, your business cannot have an EIN of its own; it must be registered to you.

To apply for an EIN you need to have an ITIN or SSN. Once you have either of these, you can apply for an EIN online directly with the IRS. You may have heard of a form called Form SS-4. This form is used for physical applications, that is to say, you physically fill out this form and then fax or mail it to the IRS instead of applying online.

Individual Taxpayer Identification Number (ITIN)

As mentioned above, you need to apply for a TIN to communicate with the IRS. However, if you are not eligible for a SSN or an EIN, you’ll most likely need to apply for an ITIN. These numbers are issued to those who cannot get SSNs or EINs. You can recognize an ITIN because it always stars with a 9 and has the number 7 or the number 8 in the fourth digit. This would be such an example: 9XX-7X-XXXX.

You’ll receive an ITIN directly from the IRS. You have to fill out IRS Form W-7 and provide proof of identity and a federal tax return. If you need help with this application, look for authorized acceptance agents who can help you. Make sure they are IRS authorized. To summarize, your ITIN application should include all of the following information:

  1. The filled-out IRS Form W-7
  2. The original, valid federal tax return (no photocopies here!)
  3. Supporting documents from an issuing agency confirming that all the information in Form W-7 is true.

If you have an SSN, you do not need an ITIN. If you have been accepted for permanent residence or US employment by US authorities, you are eligible to get an SSN (see above).

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