Your Tax ID Number Is Already Assigned — You Just Need To Locate It
A Tax ID number (also called an Employer Identification Number or EIN if you own a business, or a Social Security Number if you're an individual) is already on file with the IRS. You don't request one for the first time — you find the one you have. For individuals, this is your Social Security Number. For businesses, nonprofits, and self-employed people, it's a nine-digit number the IRS issued when you registered.
The fastest way to find it depends on what type of entity you are. Individuals can check their Social Security card or tax documents. Business owners can look at past tax returns, IRS correspondence, or request a copy from the IRS directly. The process takes minutes if you know where to look, or a few weeks if you need the IRS to send you a copy.
Key Takeaways
- Individuals use their Social Security Number as their Tax ID; it appears on your Social Security card, tax returns, and W-2 forms.
- Business owners and self-employed people have a separate nine-digit EIN that the IRS issued; check past tax returns or IRS letters first.
- You can request a copy of your EIN from the IRS by phone, mail, or through your online IRS account if you've registered one.
- The IRS will not issue a duplicate Social Security Number, but they can provide a copy of your EIN assignment letter or confirm your number by phone.
Where To Find Your Number If You're an Individual
Your Tax ID as an individual is your Social Security Number. It appears on your Social Security card, which you received from the Social Security Administration (not the IRS). If you still have that card, the number is printed on the front.
If you don't have your card, check any of these documents: your most recent tax return (Form 1040), a W-2 form from an employer, a 1099 form from a client or bank, a mortgage statement, or any letter from the IRS. All of these show your Social Security Number. You can also call the Social Security Administration at 1-800-772-1213 to confirm your number, though they will ask you security questions first.
Where To Find Your EIN If You Own a Business or Are Self-Employed
If you registered a business, nonprofit, partnership, or LLC with the IRS, you have a separate Employer Identification Number (EIN). This is a nine-digit number formatted as XX-XXXXXXX. The IRS issued it to you when you filed Form SS-4 or registered online.
Start by checking documents you already have. Look at past business tax returns (Form 1120, 1120-S, 1065, or 1040-C depending on your structure), any W-2 forms you issued to employees, or letters from the IRS about your account. Your EIN appears on all of these. If you filed taxes electronically, your tax software may have a record of it.
If you cannot find it in your records, you can request it from the IRS. The fastest method is to call the IRS Business and Specialty Tax Line at 1-800-829-4933 during business hours (Monday through Friday, 7 a.m. to 7 p.m. your local time). Have your Social Security Number and business information ready. The IRS can confirm your EIN over the phone immediately.
How To Request Your EIN From the IRS by Mail or Online
If you prefer not to call, you can request a copy of your EIN assignment letter by mail. Send a letter to the IRS address for your state (found on IRS.gov under "Where to File") that includes your name, business name, Social Security Number, and the year you think you received the EIN. The IRS will mail you a copy of your assignment letter, which shows your EIN. This takes two to four weeks.
If you have an IRS online account (created through IRS.gov), you can view your EIN there without calling or writing. Log in, go to your business account, and look for your EIN in the account information section. This is the fastest option if you've already set up an account.
What To Do If You Never Received an EIN
If you started a business but never formally registered it with the IRS, you may not have an EIN yet. In that case, you would use your Social Security Number as your business Tax ID until you register. You can obtain an EIN at any time by filing Form SS-4 online at IRS.gov, by phone at 1-800-829-4933, or by mail. Online registration is instant; phone registration takes a few minutes; mail takes two to four weeks.
You need an EIN if you have employees, operate as a corporation or partnership, or file certain types of business tax returns. If you're self-employed and operate as a sole proprietor with no employees, you can use your Social Security Number, though many people obtain an EIN anyway for privacy and business separation reasons.
Documents That Show Your Tax ID Number
| Document Type | Who It Shows | Where To Find It |
|---|---|---|
| Social Security Card | Individuals | Front of card |
| Form 1040 (Individual Tax Return) | Individuals | Top of form |
| W-2 Form | Individuals and employers | Box 1 (employee SSN) and Box b (employer EIN) |
| Form 1120 or 1120-S (Business Tax Return) | Businesses | Top of form |
| EIN Assignment Letter | Businesses | Entire letter is the confirmation |
| IRS Letter or Notice | Whoever it's addressed to | In the body of the letter |
Frequently Asked Questions
Can I get a new Tax ID number if I lost mine?
No. The IRS does not issue new Social Security Numbers or EINs. Your number is permanent. If you've lost track of it, you request a copy of your assignment letter or confirmation from the IRS, but the number itself doesn't change. Once you locate it, keep a record in a safe place.
What if I think someone used my Tax ID fraudulently?
Contact the IRS immediately at 1-800-829-1040 and file a report. You can also file an Identity Theft Report with the FTC at IdentityTheft.gov. The IRS has procedures to flag your account and investigate. Keep records of any fraudulent activity and correspondence with the IRS.
Do I need my Tax ID to file taxes?
Yes. The IRS requires your Tax ID on every tax return you file. For individuals, this is your Social Security Number. For businesses, it's your EIN. You cannot file without one, so locate it before tax season begins.
How long does it take to get an EIN if I don't have one yet?
Online registration through IRS.gov is instant — you receive your EIN immediately. Phone registration (1-800-829-4933) takes a few minutes. Mail registration takes two to four weeks. If you need it quickly, apply online or by phone.
Can I use my Social Security Number instead of an EIN for my business?
Yes, if you're self-employed with no employees and operate as a sole proprietor. However, many business owners obtain an EIN anyway to separate personal and business finances and protect their Social Security Number from unnecessary exposure on business documents.