An SSN (Social Security Number) is issued by the Social Security Administration to U.S. citizens, permanent residents, and noncitizens authorized to work in the United States. An ITIN (Individual Taxpayer Identification Number) is issued by the IRS purely for tax administration, to people who have a U.S. tax obligation but are not eligible for an SSN. Both are nine digits, but an ITIN always begins with 9 — and one person never validly holds both numbers at the same time.
ITIN vs SSN at a Glance
| Feature | SSN | ITIN |
|---|---|---|
| Issuing agency | Social Security Administration (SSA) | Internal Revenue Service (IRS) |
| Who gets it | U.S. citizens, permanent residents, noncitizens with work authorization | People with U.S. tax obligations who are not eligible for an SSN |
| Application form | Form SS-5 | Form W-7 |
| Number format | XXX-XX-XXXX (various first digits) | 9XX-XX-XXXX (always starts with 9) |
| Authorizes work | Yes | No |
| Social Security benefits | Yes (with sufficient work credits) | No |
| Expires | Never | Yes, if unused on a federal return for 3 consecutive years |
| Cost | Free | Free from the IRS; Certified Acceptance Agent fees apply if you use one |
| Typical processing time | About 2 weeks after SSA approval | ~7 weeks by mail; 9–11 weeks in peak season or from abroad |
The SSN is a work-and-benefits identity number that happens to be used for taxes. The ITIN exists only because the IRS needs a way to process returns from people who cannot get an SSN.
What an ITIN Does NOT Do
This section matters more than any comparison table. The ITIN has a narrow, specific purpose, and misunderstanding its limits causes real problems.
- An ITIN is for U.S. tax administration only. It lets the IRS process returns, payments, and refunds for people without SSNs. Nothing more.
- An ITIN does NOT authorize you to work in the United States. Employment eligibility is determined by immigration status, never by a tax number.
- An ITIN does NOT confer or change immigration status. Holding one has no effect on visas, residency, or any immigration process.
- An ITIN does NOT entitle the holder to Social Security benefits. Taxes paid under an ITIN do not accrue Social Security credits.
If you have seen claims online that an ITIN can substitute for an SSN for jobs or benefits, those claims are wrong. The IRS states these limits explicitly in the Form W-7 instructions.
Who Should Apply for Which Number
This is not a choice — eligibility determines it, and SSN eligibility always takes precedence.
You apply for an SSN if:
- You are a U.S. citizen or permanent resident (green card holder)
- You are a noncitizen with work authorization from DHS — for example, an approved employment-based visa or an Employment Authorization Document
You apply through the SSA using Form SS-5, with proof of identity, age, and immigration status; the card is free and typically arrives about two weeks after approval.
You apply for an ITIN if:
- You are not eligible for an SSN, and
- You have a federal tax filing or reporting requirement
Common ITIN scenarios include non-resident aliens filing a U.S. return (for example, owners of U.S. LLCs, sellers on U.S. marketplaces, or recipients of U.S. rental income), spouses and dependents of visa holders who are claimed on a return, and non-residents claiming tax treaty benefits. The application is Form W-7, normally attached to a federal tax return, though exceptions exist for treaty benefits, bank interest reporting, and mortgage interest. For the full eligibility breakdown, see what an ITIN number is.
Quick eligibility test
| Your situation | Number to apply for |
|---|---|
| U.S. citizen or green card holder | SSN |
| Visa with work authorization | SSN |
| Non-resident with U.S. tax filing obligation, no work authorization | ITIN |
| Foreign owner of a U.S. LLC filing a federal return | ITIN |
| Spouse or dependent of a visa holder, claimed on a U.S. return | ITIN |
| Non-resident claiming a tax treaty benefit | ITIN |
If your business needs a tax ID rather than you personally, that is an EIN — a different number entirely. The comparison in EIN vs ITIN vs SSN covers all three.
Can You Have Both? What Happens When You Become SSN-Eligible
No one validly holds an ITIN and an SSN at the same time. The IRS will not issue an ITIN to anyone eligible for an SSN, and Form W-7 requires you to declare you are not SSN-eligible.
The common transition runs in one direction: an ITIN holder later obtains work authorization or permanent residency and becomes SSN-eligible. Here is the correct sequence:
- Apply for the SSN with the SSA using Form SS-5. This is an SSA process, not an IRS one.
- Stop using the ITIN the moment the SSN is issued. Use the SSN on all future returns and tax documents.
- Notify the IRS in writing that you have received an SSN. Include your name, mailing address, both numbers, and a copy of the SSN card if possible. The IRS combines your prior tax records under the SSN and deactivates the ITIN.
Note the wording: the IRS combines records. There is no mechanism to "transfer" an ITIN into an SSN — they are different numbers from different agencies. Your filing history, payments, and refund records are merged under the new number once the IRS is notified. For credit history, the major credit bureaus can typically link prior history to your new number once you notify them; contact each bureau directly for its process.
How Each Number Is Used on Tax Returns
Functionally, both numbers occupy the same field. On Form 1040 or 1040-NR, the taxpayer identification number goes in the box at the top — an SSN for those who have one, an ITIN for those who do not. The same applies to spouses and dependents listed on the return.
Differences appear at the edges:
- Credits and benefits. Several federal tax credits have SSN requirements written into the statute. ITIN filers should review credit eligibility rules carefully each year rather than assume parity with SSN filers.
- Expiration risk. An expired ITIN on a return triggers processing delays and adjusted credits until it is renewed. An ITIN unused on a federal return for three consecutive tax years expires on December 31 of that third year. SSNs never expire. If yours has lapsed, the renewal process is covered in ITIN renewal: when and how.
- Withholding documents. Non-resident aliens use the ITIN on forms like W-8BEN when claiming treaty rates on U.S.-source income; SSN holders generally certify with Form W-9 instead.
Banking and Credit: Where the Numbers Differ in Practice
Banks must verify customer identity under Customer Identification Program (CIP) rules from the USA PATRIOT Act and Bank Secrecy Act. A taxpayer identification number is one element of that verification — and this is where ITIN holders encounter real-world friction that SSN holders do not.
- SSN holders can open accounts at essentially any U.S. institution and apply for credit anywhere.
- ITIN holders can open personal accounts at many — but not all — institutions. Chase, Bank of America, Wells Fargo, Citibank, and many credit unions are commonly cited as accepting ITINs, but policies vary by state, branch, and over time, so always confirm with the specific branch first. The full landscape is mapped in banks that accept ITIN.
Credit history works the same way mechanically for both: bureaus build a file tied to your taxpayer identification number as lenders report activity. Some credit card issuers accept ITIN applications; many do not. No outcome is guaranteed with either number, but the practical menu of options is wider with an SSN.
Interest-bearing accounts generate Form 1099-INT reporting, which is why banks ask for a TIN at account opening regardless of which type you hold.
Getting an ITIN: Mail vs Certified Acceptance Agent
If the eligibility test above points you to an ITIN, you have two practical routes:
- Mail Form W-7 directly to the IRS (ITIN Operation, P.O. Box 149342, Austin, TX 78714-9342) with your original passport or certified copies. Processing takes about 7 weeks, stretching to 9–11 weeks during peak season (January 15–April 30) or when filing from abroad — and your passport sits with the IRS for the duration. Full timelines are in how long does it take to get an ITIN.
- Apply through an IRS Certified Acceptance Agent (CAA). A CAA verifies your passport in person or remotely and submits certified copies, so the original never leaves your hands. Through a CAA such as itin.net, the application is prepared and documents verified in 5–10 business days, with a $497 flat fee and a 100% money-back guarantee.
Frequently Asked Questions
Can I have both an ITIN and an SSN at the same time?
No. A person never validly holds both at once. The IRS will not issue an ITIN to anyone eligible for an SSN. If you become SSN-eligible, you apply with the Social Security Administration, stop using the ITIN, and notify the IRS in writing so your tax records are combined under the SSN.
Does an ITIN allow me to work in the United States?
No. An ITIN does not authorize you to work in the United States. It is for U.S. tax administration only. Work authorization comes through immigration status, and people authorized to work receive an SSN from the SSA.
How can I tell an ITIN from an SSN by looking at the number?
Both are nine digits in the format XXX-XX-XXXX, but an ITIN always begins with 9. SSNs start with various other digits, never in the ITIN's reserved range.
Who issues the ITIN and who issues the SSN?
The IRS issues ITINs through Form W-7. The Social Security Administration issues SSNs through Form SS-5. They are separate agencies with entirely separate application processes and eligibility rules.
Does an ITIN expire?
Yes. An ITIN not used on a federal tax return for three consecutive tax years expires on December 31 of that third year. It can be renewed with Form W-7 by checking the "Renew an Existing ITIN" box. SSNs never expire.
Does an SSN expire if I leave the United States?
No. An SSN is assigned for life and remains valid even if you leave the country permanently or stop working.
Does an ITIN affect my immigration status?
No. An ITIN does not confer or change immigration status in any way. The IRS issues it purely so people without SSNs can meet their U.S. tax obligations.
What happens to my tax history if I get an SSN after using an ITIN?
You notify the IRS in writing that you have received an SSN, listing both numbers. The IRS combines your prior filing history, payments, and refund records under the new SSN, and the ITIN is deactivated.
Is it free to get an ITIN or an SSN?
Both are free directly from the government — the SSA charges nothing for Form SS-5 and the IRS charges nothing for Form W-7. Fees apply only if you choose to use a Certified Acceptance Agent or other professional to prepare and certify the ITIN application.
Can a non-resident with no U.S. immigration status get an SSN?
Generally no. SSNs are issued only to U.S. citizens, permanent residents, and noncitizens with work authorization. Non-residents with U.S. tax obligations but no SSN eligibility use an ITIN to file instead.
