What Is an NPI Number? How to Verify Healthcare Providers

If you've ever looked closely at a medical bill, explanation of benefits, or insurance claim, you've probably seen a 10-digit number labeled "NPI." Most people gloss right over it. But that number is actually one of the most useful tools available for verifying that a healthcare provider is who they say they are -- and it's completely free to look up.

What Is an NPI Number?

NPI stands for National Provider Identifier. It's a unique 10-digit number assigned to every healthcare provider in the United States who transmits health information electronically. That includes doctors, dentists, nurses, therapists, pharmacists, chiropractors, optometrists, hospitals, clinics, nursing homes, and medical equipment suppliers -- essentially anyone involved in delivering or billing for healthcare.

The NPI system was created by the Health Insurance Portability and Accountability Act of 1996 (HIPAA). Before NPI numbers existed, there was no single, standardized way to identify healthcare providers across the country. Different insurance companies, Medicare, Medicaid, and state agencies all used their own numbering systems. A single doctor might have had a dozen different ID numbers depending on which payer they were dealing with.

The NPI replaced all of that. Starting May 23, 2007, every covered healthcare provider was required to obtain an NPI and use it on all electronic transactions -- claims, referrals, prescriptions, eligibility checks, and more. One number, one provider, nationwide.

The Two Types of NPI Numbers

There are two categories of NPI, and the distinction matters:

Type 1 NPI is assigned to individual providers. This is what your personal doctor, dentist, or therapist has. It's tied to the person, not to any organization they work for. If a physician moves from one hospital to another, their Type 1 NPI goes with them. It stays the same for their entire career.

Type 2 NPI is assigned to organizations -- hospitals, clinics, group practices, nursing facilities, home health agencies, and other healthcare entities. A Type 2 NPI identifies the organization rather than any individual provider within it.

Many providers have both. A surgeon, for example, has their own Type 1 NPI as an individual, and the hospital where they practice has a Type 2 NPI as an organization. Both numbers might appear on a single claim.

What the NPPES Registry Is

The National Plan and Provider Enumeration System (NPPES) is the federal database that assigns, stores, and publishes NPI records. It's maintained by the Centers for Medicare and Medicaid Services (CMS), and it's freely accessible to anyone.

This is important: the NPPES registry is not a credentialing database. It doesn't verify that a provider is licensed, board-certified, or in good standing. It confirms that someone has been assigned an NPI number and shows the information they reported when they applied for it. Think of it as a directory, not a seal of approval.

That said, the data in NPPES is still enormously useful for verification purposes, as we'll get into below.

How to Look Up a Provider by NPI

The official lookup tool is at npiregistry.cms.hhs.gov. It's free, requires no account, and is available to anyone. Here's how to use it:

Searching by NPI Number

If you already have the NPI number (from a bill, prescription, or referral), you can enter it directly into the search tool. This is the most precise search -- it will return exactly one result because NPI numbers are unique.

Searching by Provider Name

If you don't have the NPI number, you can search by name. For individual providers, enter their first and last name. For organizations, enter the business name. You can narrow results by state, city, and provider type (taxonomy).

Common name searches will return multiple results, so adding location or specialty information helps you find the right person.

Searching by Specialty

The NPPES uses a standardized taxonomy system to classify provider types and specialties. You can search by taxonomy to find, say, all cardiologists in a particular city. This is less useful for verifying a specific provider but can be helpful if you're looking for providers in your area.

What Information an NPI Record Contains

When you pull up an NPI record, here's what you'll typically see:

• NPI number -- the unique 10-digit identifier
• Provider name -- for Type 1, this is the individual's legal name along with any credentials (MD, DO, DDS, RN, etc.). For Type 2, it's the organization's legal business name
• Provider type -- individual (Type 1) or organization (Type 2)
• Taxonomy codes and descriptions -- these indicate the provider's specialty and area of practice. A single provider can have multiple taxonomy codes (for example, a doctor who practices both internal medicine and geriatrics)
• Practice address -- the location where the provider delivers services
• Mailing address -- which may be different from the practice address, especially for providers who use a billing service
• Phone and fax numbers
• Enumeration date -- when the NPI was first assigned
• Last update date -- when the record was most recently modified
• Gender -- for individual providers
• Authorized official -- for organizations, the person who is authorized to manage the NPI record
• Other identifiers -- some records include legacy identifiers like Medicare UPIN numbers or state license numbers, though this information is not always present

One thing you won't find: NPI records do not include the provider's medical school, residency training, board certifications, malpractice history, or disciplinary actions. For that level of detail, you need to check other sources (more on that below).

Why NPI Lookup Matters for Patients

There are several practical reasons why looking up a provider's NPI is worth your time:

Verifying Provider Identity

If you're seeing a new doctor, therapist, or specialist, an NPI lookup confirms basic facts: Is this person actually a registered healthcare provider? Does their stated specialty match what's in the federal database? Is their practice location where they say it is?

This is particularly important for telehealth. When you're receiving care from someone you've never met in person, an NPI lookup is a quick sanity check that the person on the other end of the video call is a real, registered provider.

Checking Bills and Insurance Claims

Medical billing errors are common -- by some estimates, a significant percentage of medical bills contain at least one mistake. If a bill lists an NPI you don't recognize, or if the NPI on a claim doesn't match the provider you actually saw, that's worth investigating. It could be a simple billing error, or it could indicate something more concerning.

Identifying Fraud

Healthcare fraud is a real problem. The Department of Justice recovers billions of dollars annually from fraudulent billing schemes. Some common fraud patterns that NPI lookup can help detect:

• Bills from providers you never saw
• NPI numbers that don't exist in the registry
• NPI records where the specialty doesn't match the services billed
• Services billed under an individual NPI when you were treated at a facility

Red Flags to Watch For

When you look up a provider's NPI, here are warning signs that warrant further investigation:

No record found. If someone claims to be a healthcare provider but has no NPI, that's a serious red flag. Every provider who bills insurance is required to have one. The only exceptions are providers who don't accept any form of insurance and don't submit electronic claims -- which is rare.

Deactivated NPI. NPI records can be deactivated for various reasons, including the provider's death, retirement, or loss of licensure. If you're being billed by a deactivated NPI, something is wrong.

Mismatched specialty. If someone tells you they're a cardiologist but their NPI taxonomy shows they're registered as a general practitioner, that's worth questioning. It doesn't necessarily mean fraud -- providers sometimes don't update their taxonomy codes -- but it's worth verifying through your state's licensing board.

Mismatched location. If the practice address on the NPI record doesn't match where you're receiving care, ask about it. There could be a legitimate explanation (the provider works at multiple locations), but it's worth understanding.

Very recent enumeration date with claims of long experience. If someone says they've been practicing for 20 years but their NPI was assigned last year, that's unusual. It's possible they were late getting an NPI or had a previous one deactivated, but it's worth asking about.

Going Beyond NPI: Full Provider Verification

An NPI lookup is a good starting point, but it's not a complete background check on a healthcare provider. For a thorough verification, you should also check:

State medical board. Every state has a medical board (or equivalent agency for dentists, nurses, etc.) that maintains a public database of licensed providers. These databases show license status, disciplinary actions, malpractice judgments, and sometimes education history. This is the single most important check you can do.

Board certification. Being board-certified in a specialty is voluntary but indicates that a provider has passed rigorous examinations in their field. You can verify board certification through the American Board of Medical Specialties (ABMS) at certificationmatters.org.

Medicare opt-out list. If a provider has opted out of Medicare, they've signed an affidavit agreeing not to bill Medicare for any services. This is legal and sometimes done by providers in concierge or cash-pay practices, but it's worth knowing about.

OIG exclusion list. The Office of Inspector General maintains a list of providers who have been excluded from participating in federal healthcare programs due to fraud, patient abuse, or other serious offenses. This is searchable at oig.hhs.gov.

People search services. Tools like OpenDataUSA can provide additional context about a provider through public records -- business registrations, professional licenses across states, and other publicly available information. This can be useful for understanding a provider's full professional footprint, especially if they practice in multiple states.

NPI for Healthcare Professionals

If you're a healthcare provider who needs an NPI or needs to update your existing record, the process is straightforward:

Getting an NPI. Apply online through the NPPES website. You'll need your Social Security Number (for Type 1) or Employer Identification Number (for Type 2), along with your practice information, taxonomy codes, and contact details. There is no fee. Processing typically takes a few days to a few weeks.

Updating your NPI. If your practice address, specialty, or other information changes, you're required to update your NPI record within 30 days. Log into the NPPES website to make changes. Keeping your record current is not just a regulatory requirement -- it helps patients find and verify you.

Deactivating an NPI. If you retire from practice or no longer need your NPI for other reasons, you should request deactivation rather than simply abandoning the record. This prevents potential misuse of your NPI number.

Common Questions About NPI Numbers

Does everyone who provides healthcare have an NPI? Not necessarily. The requirement applies to providers who transmit health information electronically in connection with transactions covered by HIPAA. Some providers who operate entirely on a cash basis and never submit electronic claims may not have one, though this is uncommon.

Can an NPI number be reused? No. Once assigned, an NPI is permanently associated with that provider, even after deactivation. Deactivated numbers are not reassigned to other providers.

Is NPI lookup really free? Yes, completely. The NPPES registry is a public service maintained by CMS. There is no charge to search it, no account required, and no limit on the number of lookups you can perform.

Does having an NPI mean a provider is qualified? No. An NPI is an administrative identifier, not a credential. It means the provider has registered with the federal system. It does not verify their education, training, licensure, or competence. Always check state licensing boards for that information.

The Bottom Line

NPI numbers are one of those behind-the-scenes elements of the healthcare system that most patients never think about. But the NPPES registry is a genuinely useful, completely free tool for verifying healthcare providers. It takes about 30 seconds to look up a provider, and the information you find can help you confirm their identity, understand their specialty, and spot potential billing problems.

Combined with state medical board checks and other verification tools, an NPI lookup is a smart step in taking an active role in your own healthcare. It won't tell you whether a provider is good at their job, but it will tell you whether they are who they claim to be.

For more ways to verify professionals and look up public records, check out our guides to professional license verification and understanding public records.