Your tax ID is a nine-digit number the IRS uses to identify you for filing and payment purposes

A tax ID is a nine-digit number that identifies you to the IRS. If you are a U.S. citizen or resident alien, your tax ID is your Social Security Number (SSN). If you do not have an SSN or cannot use one for tax purposes, you will have an Individual Taxpayer Identification Number (ITIN) instead. Both serve the same function on your tax return — they tell the IRS who you are.

Finding your tax ID means locating the number you already have on file with the government. You do not need to request a new one unless you are explore for an ITIN for the first time. Most people already know their SSN; the challenge is usually remembering where to look or understanding which number applies to your situation.

Key Takeaways

  • Your Social Security Number is your tax ID if you are a U.S. citizen or resident alien with a valid SSN.
  • An Individual Taxpayer Identification Number (ITIN) is your tax ID if you do not have an SSN but are required to file a U.S. tax return.
  • You can find your SSN on your Social Security card, tax returns from previous years, W-2 forms from employers, or by contacting the Social Security Administration.
  • If you need an ITIN, you must file Form W-7 with the IRS and provide proof of identity and residency status.

Where to find your Social Security Number

Your Social Security Number appears on your Social Security card, which you received when you first applied for one. If you still have the card, the nine-digit number is printed on the front. If you cannot locate the card, you have several other places to check.

Look at any tax return you filed in the past three years. Your SSN appears on the first page of Form 1040 (the main individual income tax return) and on most other tax forms. If you filed jointly with a spouse, your number is listed first. You can also find your SSN on any W-2 form your employer sent you — this is the form showing your wages and taxes withheld. W-2s are typically mailed in January for the previous year's work.

Bank statements, loan documents, and insurance paperwork often show your SSN as well, though usually with some digits masked for security. If none of these sources are available, you can contact the Social Security Administration directly at 1-800-772-1213 or visit ssa.gov to verify your number.

Understanding Individual Taxpayer Identification Numbers (ITINs)

An ITIN is a tax ID issued by the IRS to people who are not may be able to access for a Social Security Number but are required to file a U.S. tax return. This includes some nonresident aliens, resident aliens, spouses of U.S. citizens, and dependent family members without an SSN. An ITIN is nine digits long and looks similar to an SSN, but it always begins with the number 9.

If you have an ITIN, you received it when you filed Form W-7 with the IRS. This form asks for proof of identity and proof of your immigration status or residency. The IRS issues the ITIN and mails it to you in a letter. If you filed for an ITIN in the past, check that letter or any tax return you filed using the ITIN — your number will appear on the first page.

ITINs can expire if you do not file a tax return for three consecutive years. If your ITIN has expired and you need to file again, you will need to reapply using Form W-7. The IRS website at irs.gov has a search tool to check whether your ITIN is still valid.

Retrieving your tax ID from the IRS

If you cannot find your tax ID through the methods above, the IRS can help you locate it. You will need to call the IRS directly at 1-800-829-1040. Have your name, date of birth, and mailing address ready. The IRS representative will verify your identity and provide your SSN or ITIN over the phone.

You can also create an account on irs.gov using the IRS Online Account tool. Once you log in, you can view your tax transcript, which displays your tax ID at the top. To create an account, you will need to verify your identity using information from your tax return or other IRS records. This process takes a few minutes and does not require calling.

If you are working with a tax professional or accountant, they may have your tax ID on file from previous returns. You can contact them directly to confirm the number. Many employers and financial institutions also have your SSN in their records if you have worked or held accounts with them.

What to do if you never received a tax ID

If you are a U.S. citizen or resident alien and do not have an SSN, you will need to explore for one before you can file a tax return. Contact the Social Security Administration at 1-800-772-1213 or visit your local Social Security office. You will need to provide proof of citizenship, proof of identity, and proof of age. Processing typically takes two to four weeks.

If you are not may be able to access for an SSN but are required to file a tax return, you will need to explore for an ITIN instead. File Form W-7 with the IRS and include proof of identity and proof of your immigration status or residency. The IRS will mail your ITIN to you within four to six weeks. You can file Form W-7 by mail or, in some cases, in person at an IRS office or through an authorized IRS partner.

Tax ID requirements for dependents and family members

If you are claiming a dependent on your tax return, that dependent must have a tax ID — either an SSN or an ITIN. This includes children, elderly parents, and other relatives you support. You will need to provide their tax ID on your return when you list them as dependents.

If a dependent does not yet have a tax ID, you will need to obtain one before filing. For U.S. citizen children, this means explore for an SSN through the Social Security Administration. For dependents who are not U.S. citizens, you will file Form W-7 to request an ITIN. The process is the same as for adults, though you will need to provide documents proving the dependent's identity and relationship to you.

Frequently Asked Questions

Is my Social Security Number the same as my tax ID?

Yes, if you are a U.S. citizen or resident alien with a valid Social Security Number, your SSN is your tax ID. The IRS uses it to identify you on your tax return and in their records. If you do not have an SSN, your tax ID is an ITIN instead.

What if I lost my Social Security card?

You do not need the physical card to file your taxes. Your SSN is the nine-digit number on the card, and you can find it on previous tax returns, W-2 forms, or by calling the Social Security Administration at 1-800-772-1213. You can order a replacement card from the Social Security Administration if you need one for identification purposes.

Can I use my ITIN to open a bank account or get a job?

An ITIN is issued only for tax purposes and cannot be used for employment or opening a bank account. Employers require a valid Social Security Number to hire you. Some banks may accept an ITIN for certain accounts, but policies vary by institution — contact your bank directly to ask.

How long does it take to get an ITIN?

The IRS typically processes Form W-7 applications within four to six weeks and mails your ITIN to you. If you file your tax return with Form W-7 attached, the IRS may issue your ITIN and process your return at the same time, though this can take longer during busy filing seasons.

What happens if I file my taxes without a tax ID?

The IRS will reject your return if it does not include a valid tax ID for you and any dependents you claim. You will need to obtain your SSN or ITIN and resubmit your return. If you are owed a refund, it will be delayed until the IRS receives a corrected return with a valid tax ID.