Self-Employed Tax ID Number: How to Apply, Use, and Update It

A self-employed tax ID number is an Employer Identification Number (EIN), a free nine-digit number the IRS issues so you can identify your business on tax forms without handing out your Social Security number. Freelancers, independent contractors, and sole proprietors can apply directly through the IRS in about five minutes online. The number then goes on your W-9s, invoices, and bank paperwork in place of your SSN.

Do You Actually Need One

If you’re a sole proprietor with no employees, you’re not legally required to have an EIN. You can file Schedule C, open some bank accounts, and complete W-9s using your Social Security number alone. The IRS only requires an EIN when specific triggers apply:

You hire employees and put them on payroll.
You form an LLC, partnership, or corporation.
You file excise, alcohol, tobacco, or firearms tax returns.
You withhold taxes on income paid to a nonresident alien.
You set up a Keogh plan or certain other retirement plans.

Even without a trigger, many self-employed people get an EIN voluntarily for privacy. Every W-9 you send with your SSN puts your most sensitive financial identifier in the hands of a client whose data security you don’t control. An EIN lets you complete the same W-9 without exposing your SSN.¹

What to Have Ready Before You Apply

The application is built around IRS Form SS-4. Gathering the details first keeps the process short:²

Your legal name exactly as it appears on your Social Security card.
A trade name if your business uses a “Doing Business As” name that differs from your legal name.
A physical mailing address for IRS correspondence.
Your SSN or ITIN, since the IRS links every EIN to a real person called the “responsible party.”³
The reason you’re applying (starting a business, hiring employees, forming an LLC).
Your business start date and entity type.

For a sole proprietor or single-member LLC, the responsible party is you. The IRS uses the EIN to track the tax accounts of employers and entities that file business returns, including businesses with no employees at all.⁴

How to Apply

Online

The IRS online portal is the fastest option and issues your EIN immediately when you finish. The system is open Monday through Friday, 6:00 a.m. to 1:00 a.m. the following day; Saturday, 6:00 a.m. to 9:00 p.m.; and Sunday, 6:00 p.m. to midnight (all Eastern time). Save the confirmation notice as soon as it appears; you may not be able to get another copy in the same format.⁵

The IRS limits online applications to one EIN per responsible party per day. If you need EINs for more than one entity, come back another day or use fax or mail for the extras.⁵

Fax

Fax a completed Form SS-4 to the IRS and you’ll typically receive your EIN within four business days, provided you include a return fax number.⁶

Mail

Mailing Form SS-4 takes about four weeks. Send it to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999.⁶

International Applicants

If you have no legal residence or principal place of business in the United States, the online tool won’t work for you. Call the IRS at 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern time. Have a completed Form SS-4 ready, because the representative will walk through it line by line and assign the EIN over the phone.³

The IRS never charges for an EIN. If a website wants a fee, it’s a third-party service marking up a free government process.⁵

What to Use Your EIN For

The most immediate use for a freelancer is Form W-9. Clients need a valid taxpayer identification number before they pay you, and an EIN satisfies that requirement in place of your SSN.¹

Most banks require an EIN to open a business checking or savings account, and some local agencies ask for one on license and permit applications. At tax time, your EIN goes on line D of Schedule C (Form 1040), where sole proprietors report business income and expenses.⁷ A dedicated business number also helps if you want to build business credit separate from your personal credit history.

If You Lose It

Check the original confirmation notice the IRS sent when the number was assigned. Prior tax returns and any IRS correspondence to your business will show it as well. If you can’t find it anywhere, call the IRS Business and Specialty Tax Line at 800-829-4933, Monday through Friday, 7:00 a.m. to 7:00 p.m. local time. Be ready to verify your identity as the responsible party before the agent releases the number.⁸

Updating or Closing the Account

An EIN is permanent. Once assigned, it can never be cancelled, reused, or transferred to a different entity, even if you shut the business down.⁹

If your business address changes or a different person takes over as the responsible party, file Form 8822-B with the IRS within 60 days of the change. Otherwise the agency keeps mailing notices to the wrong place.¹⁰

To close the account, send a letter to Internal Revenue Service, Cincinnati, OH 45999 with your business’s legal name, EIN, address, and reason for closing. Include a copy of the original EIN confirmation notice if you have it. The IRS won’t close the account until all required returns have been filed and all taxes paid.¹¹

1
Internal Revenue Service. Form W-9 – Request for Taxpayer Identification Number and Certification
2
Internal Revenue Service. Instructions for Form SS-4 – Application for Employer Identification Number
3
Internal Revenue Service. Instructions for Form SS-4 (12/2025)
4
Internal Revenue Service. Understanding Your EIN
5
Internal Revenue Service. Get an Employer Identification Number
6
Internal Revenue Service. Employer Identification Number
7
Internal Revenue Service. Schedule C (Form 1040) – Profit or Loss From Business
8
Taxpayer Advocate Service. TAS Tax Tip – Employer Identification Numbers
9
Internal Revenue Service. If You No Longer Need Your EIN
10
Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party
11
Internal Revenue Service. Closing a Business