To get a provider tax ID number, apply for an Employer Identification Number (EIN) with the IRS. The fastest route is the free online application at irs.gov, which runs Monday through Friday and issues the nine-digit number immediately once you finish the interview. The whole process takes about 10 to 15 minutes if you have your information ready. The EIN identifies your practice as a business entity for tax filing, insurance billing, payroll, and banking, and payers use it alongside your NPI on claims and 1099s.
Do You Actually Need an EIN
A solo practitioner with no employees and no retirement plan can use a Social Security Number for tax purposes. An EIN becomes mandatory the moment any of these applies:
- You hire employees. Even one part-time medical assistant or receptionist triggers the requirement.
- You operate as a corporation, partnership, or multi-member LLC. These entity types cannot use a personal SSN for business tax filings.
- You establish a retirement plan. A solo 401(k) or SEP-IRA for your practice needs a separate EIN.
- You file excise or employment tax returns, including withholding from employee wages.
Most solo providers get one anyway. Handing your SSN to every insurance company, billing clearinghouse, and vendor creates identity theft exposure that a separate business number avoids. Banks also typically require an EIN to open a business checking account.
The EIN Is Not Your NPI
New practitioners sometimes confuse the two. Your EIN identifies your business entity for taxes and financial transactions. Your National Provider Identifier (NPI) identifies you as a clinical provider in HIPAA-standard transactions: claims, eligibility checks, referrals, and remittance advice. The NPI is a 10-digit number issued by the Centers for Medicare and Medicaid Services, not the IRS, and federal regulations require every covered healthcare provider to obtain one and use it on all standard transactions.1eCFR. 45 CFR 162.410 – Implementation Specifications: Health Care Providers Individual providers apply as Entity Type 1; organizations apply as Entity Type 2.2Centers for Medicare & Medicaid Services. The Who, What, When, Why and How of NPI You register for the NPI through the National Plan and Provider Enumeration System at nppes.cms.hhs.gov. Getting one number does not substitute for getting the other, and the processes are entirely separate.
Information You Need Before Applying
Gather this before you sit down at the application, because the online system times out if you pause too long:
- Responsible party. The person who has ultimate control over the entity. For a solo practice, that’s you; for a partnership or corporation, it’s typically a principal officer or general partner. The responsible party must provide a Social Security Number or Individual Taxpayer Identification Number.3Internal Revenue Service. Responsible Parties and Nominees
- Legal name of the entity, exactly as it appears on your formation documents, plus any trade name or DBA if the practice uses a different public-facing name.
- Physical street address of the practice, plus a mailing address. A P.O. Box works for mail, but the IRS also needs the actual location.
- Entity type: sole proprietorship, partnership, corporation, LLC, or another structure. Your choice determines which tax return forms you file and how income flows to your personal return.4Internal Revenue Service. Business Structures
- Reason for applying: starting a new practice, hiring employees, banking purposes, or another qualifying reason.
- Closing month of your accounting year. Most medical practices use December.
Double-check that every name and number matches exactly what’s on file with the Social Security Administration. Mismatches are the most common reason applications get rejected, and they’re the easiest problem to prevent.
If You Don’t Have a Social Security Number
Providers who aren’t eligible for an SSN can apply for an Individual Taxpayer Identification Number using IRS Form W-7, submitted with a federal income tax return and documents proving foreign status and identity. You can apply by mail to the IRS ITIN Operation in Austin, Texas, or in person at an IRS Taxpayer Assistance Center.5Internal Revenue Service. How to Apply for an ITIN Processing takes about seven weeks, or up to eleven weeks during tax season (January 15 through April 30). You need the ITIN before you can submit an EIN application, so plan around that timeline.
How to Submit the Application
The application is IRS Form SS-4. You have three ways to submit if you’re based in the United States, plus a phone option for international applicants.6Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
Online
The IRS online EIN application is available Monday through Friday, 6:00 a.m. to 1:00 a.m. Eastern Time the following day. You answer interview-style questions, review a summary page, and receive your EIN immediately upon submission. One catch: the IRS allows only one EIN per responsible party per day through the online system, so if you’re setting up multiple entities, space out your applications.7Internal Revenue Service. Get an Employer Identification Number
Fax
Complete Form SS-4 and fax it in. For applicants in any of the 50 states or the District of Columbia, the fax number is 855-641-6935. International applicants use 855-215-1627 from within the U.S. or 304-707-9471 from outside.8Internal Revenue Service. Where to File Your Taxes for Form SS-4 Include your return fax number on the form. You should receive your EIN within four business days.9Internal Revenue Service. Instructions for Form SS-4 (12/2025)
Send the completed, signed Form SS-4 to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999.8Internal Revenue Service. Where to File Your Taxes for Form SS-4 Allow approximately four weeks for processing.9Internal Revenue Service. Instructions for Form SS-4 (12/2025) It’s the slowest route, but it works if you have no internet access or fax.
Phone for International Applicants
If you have no legal residence or principal place of business in the United States, call 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern Time. Have Form SS-4 filled out before you call. The representative walks through the form with you and assigns your EIN during the call.9Internal Revenue Service. Instructions for Form SS-4 (12/2025) The IRS no longer issues EINs by phone for domestic applicants.
The IRS Charges Nothing for This
An EIN is free. There is no application fee, no processing charge, and no expediting fee.10Internal Revenue Service. Employer Identification Number If a website asks you to pay, you’re not on the IRS site. The Federal Trade Commission has warned consumers about companies charging hundreds of dollars for what is a free service.11Federal Trade Commission. Don’t Pay to Get Your Employer Identification Number (EIN) Always start at irs.gov and navigate to the EIN application from there.
After You Get the Number
Online applicants can download or print the confirmation on the spot. Fax applicants get their number faxed back within four business days. Mail applicants wait roughly four weeks.
However you applied, the IRS also sends a CP 575 confirmation notice by mail. That’s the official paper record of your EIN assignment. Store it somewhere secure. Banks, insurance credentialing departments, and payers routinely ask for it when verifying your practice’s legitimacy.
If You Lose Your EIN
Misplaced numbers are common, especially for providers who applied years ago. The IRS suggests checking the original CP 575 notice, prior business tax returns, the bank where your business account is held, or state agencies where you applied for licenses.10Internal Revenue Service. Employer Identification Number
If none of that works, 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 (Alaska and Hawaii follow Pacific Time). After verifying your identity, they can provide your EIN over the phone and send a 147C letter as replacement verification.10Internal Revenue Service. Employer Identification Number
Keeping Your EIN Information Current
An EIN doesn’t expire, but the information tied to it has to stay accurate. Practices most often need to update two things: the address and the responsible party.
If the person designated as your responsible party changes, notify the IRS within 60 days by filing Form 8822-B.12Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business This comes up when a practice changes ownership, brings on a new managing partner, or when the original responsible party leaves. The form asks for both the old and new responsible party’s name and taxpayer identification number.13Internal Revenue Service. Form 8822-B, Change of Address or Responsible Party – Business
Address changes also go on Form 8822-B. Keep the address current because the IRS mails notices about filing deadlines, penalties, and account issues to whatever address it has on file. If those notices go to your old office, something is going to slip.