Tax ID Number vs. EIN: What's the Difference

A Tax ID Number and an EIN Are Not Quite the Same Thing

A Tax ID Number is the broad category. An EIN — Employer Identification Number — is one specific type of Tax ID Number that the IRS issues to businesses and certain organizations. If you are a sole proprietor with no employees, you might use your Social Security Number as your Tax ID instead. If you run a partnership, LLC, or corporation, you need an EIN. The confusion happens because people often use "Tax ID" and "EIN" interchangeably, but they are not identical.

The IRS recognizes several kinds of Tax ID Numbers depending on who you are and what you do. Understanding which one you need matters because using the wrong number on tax forms or with your bank can delay processing and create compliance problems.

Key Takeaways

A Tax ID Number is the umbrella term; an EIN is one specific type issued by the IRS to businesses, partnerships, and certain organizations.
Sole proprietors without employees can use their Social Security Number as a Tax ID, but many choose to get an EIN instead for privacy and business separation.
The IRS issues different Tax ID Numbers for different purposes: EINs for businesses, ITINs for non-citizens, SSNs for individuals, and others for specific situations.
You need an EIN to open a business bank account, hire employees, or file certain business tax forms, even if you are a sole proprietor.

The Five Main Types of Tax ID Numbers the IRS Issues

The IRS uses five primary Tax ID Numbers. An EIN goes to businesses, partnerships, corporations, nonprofits, and trusts. A Social Security Number (SSN) is issued by the Social Security Administration and serves as a Tax ID for individuals and sole proprietors. An ITIN — Individual Taxpayer Identification Number — goes to non-citizens who do not have an SSN but need to file taxes or open a bank account. An ATIN — Adoption Taxpayer Identification Number — is temporary and issued to adoptive parents before a child's SSN arrives. An PTIN — Preparer Tax Identification Number — is for tax return preparers only.

For most people asking this question, the choice is between using an SSN or getting an EIN. If you are self-employed and have no employees, the IRS allows you to use your SSN on your tax return. However, many sole proprietors get an EIN anyway because it keeps their personal and business finances separate and protects their SSN from being shared with vendors and clients.

When You Must Have an EIN Instead of Just a Tax ID

Certain situations require an EIN specifically. If you operate as a partnership, LLC, S-corporation, or C-corporation, you must have an EIN — you cannot use an SSN. If you hire any employees, you need an EIN to report payroll taxes. If you open a business bank account, most banks require an EIN or will ask for one. If you file certain business tax forms — such as Form 1065 for partnerships or Form 1120 for corporations — you must use an EIN.

Nonprofits, trusts, and estates also need EINs. If you are a sole proprietor with no employees and no business bank account, you can file your taxes using your SSN, but you may still choose to get an EIN for privacy reasons or to keep business and personal finances clearly separated.

How to Get an EIN From the IRS

You can get an EIN for free from the IRS in three ways. The fastest is online at irs.gov using Form SS-4. You fill out the form, submit it, and receive your EIN immediately on screen. You can also call the IRS Business and Specialty Tax Line at 1-800-829-4933 during business hours and receive your EIN by phone. The slowest method is mailing a completed Form SS-4 to the IRS, which takes about four weeks.

You do not need a lawyer, accountant, or paid service to get an EIN. The IRS issues it directly and at no cost. Have your Social Security Number, business address, and information about your business structure ready before you start. If you are applying online, you will need to know your expected first month of business operation and the type of business you run.

Why Some Sole Proprietors Get an EIN Even When They Do Not Have To

A sole proprietor with no employees can legally file taxes using only their SSN. However, many choose to get an EIN for practical reasons. An EIN keeps your Social Security Number off business documents, invoices, and vendor records, reducing identity theft risk. It also makes it easier to separate personal and business finances when you open a business bank account — many banks prefer or require an EIN for business accounts.

An EIN also signals to clients and vendors that you are running a formal business, which can improve credibility. If you ever plan to hire employees, take on business partners, or change your business structure, having an EIN already in place simplifies the transition. There is no downside to getting one, and the process takes minutes online.

What Happens If You Use the Wrong Tax ID Number

Using the wrong Tax ID Number creates problems. If you are required to have an EIN but file taxes or open a bank account using your SSN instead, the IRS may reject your return or the bank may refuse the account. If you use someone else's Tax ID Number, you commit fraud. If you use an SSN on a business form that requires an EIN, the form may be returned as incomplete or incorrect.

The fix is usually straightforward: get the correct Tax ID Number and resubmit. However, this causes delays in processing, tax filing, or account opening. If you are unsure which Tax ID Number you need, contact the IRS directly or consult a tax professional before submitting forms or opening accounts.

Frequently Asked Questions

Can I use my Social Security Number instead of an EIN for my business?

Only if you are a sole proprietor with no employees and no business partners. Partnerships, LLCs, corporations, nonprofits, and any business with employees must have an EIN. Even as a sole proprietor, many choose to get an EIN anyway for privacy and to separate personal and business finances.

How long does it take to get an EIN?

Online applications through irs.gov are instant — you receive your EIN immediately on screen. Phone applications take a few minutes during the call. Mail applications take about four weeks. There is no cost for any method.

Do I need an EIN to open a business bank account?

Most banks require an EIN or will ask for one when you open a business account. Some banks may accept an SSN from a sole proprietor, but they typically prefer an EIN. Check with your bank before applying, but it is usually easier to get an EIN first.

What is an ITIN and how is it different from an EIN?

An ITIN is an Individual Taxpayer Identification Number issued to non-citizens who do not have a Social Security Number but need to file taxes or open a bank account in the United States. An EIN is for businesses and organizations. They serve different purposes and are issued to different groups of people.

Can I change my Tax ID Number after I start my business?

You can get a new EIN if your business structure changes — for example, if you convert from a sole proprietorship to an LLC. However, you cannot simply swap one Tax ID for another without a business reason. Changing Tax ID Numbers creates confusion with the IRS and your bank, so only do it if your business structure actually changes.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.