What Is an NPI Number?
An NPI (National Provider Identifier) is a permanent, unique 10-digit number assigned to every US healthcare provider by CMS under HIPAA. Required for Medicare and Medicaid billing since 2008. Administered through the free public NPPES registry — searchable by name, specialty, or location.
What an NPI is — and what it is not
The National Provider Identifier is a federal administrative number — nothing more, nothing less. It does not grant prescribing authority, licensure, or hospital privileges. It does not indicate that a provider is currently practicing, in good standing, or free from sanctions. It is purely an identifier: a way for CMS, insurers, hospitals, and pharmacies to reference a specific provider consistently across electronic transactions.
Think of it like an employer identification number (EIN) but for healthcare providers. Every physician has one. Every physical therapy practice has one. Every hospital has one. The 10-digit format is standardized, permanent, and public — searchable by anyone at no cost through the NPPES registry at nppes.cms.hhs.gov.
The NPI replaced an older patchwork of provider identifiers — UPIN numbers, Medicare provider numbers, Medicaid legacy IDs — that differed by payer and created substantial administrative friction. HIPAA's Administrative Simplification provisions mandated a single national standard beginning in 2004; full adoption was required by May 2008 for most covered entities.
Type 1 vs. Type 2 NPI
There are two categories. The first digit of an NPI indicates which type it is:
Assigned to a single human healthcare provider: physician, dentist, nurse practitioner, chiropractor, therapist, pharmacist, or any other individual who provides health services.
First digit: 1
Assigned to a healthcare organization: group practice, hospital, pharmacy, home health agency, skilled nursing facility, or any entity that provides health services through its employees or contractors.
First digit: 2
An individual physician in a group practice may have their own Type 1 NPI andbill under the group's Type 2 NPI. Both numbers exist simultaneously in NPPES.
Structure of an NPI
Every NPI is exactly 10 digits. The structure is defined in 45 CFR § 162.406:
The Luhn algorithm is the same mathematical check used on credit card numbers. It catches most single-digit transcription errors. If the check digit doesn't match the body digits, the NPI is invalid.
Where NPIs come from: NPPES
The National Plan and Provider Enumeration System (NPPES) is the federal registry that issues and maintains NPIs. It is administered by HRSA on behalf of CMS under the authority of 45 CFR Part 162. NPPES is free to search — the entire dataset is published as a monthly bulk download (public domain under 17 U.S.C. § 105) and as an API at npiregistry.cms.hhs.gov. There is no fee to apply for an NPI, no renewal requirement, and no expiration.
Each NPPES record includes: the NPI number, provider type (Type 1 or 2), name, credential, primary practice address, mailing address, enumeration date, taxonomy codes (specialty classifications), other identifiers (state license numbers, Medicare UPIN legacy), and authorized officials for organizations. The full public file contains over 8 million provider records.
Look up an NPI
Search any US provider by NPI number, name, or specialty — returns NPPES record details, CMS PECOS enrollment status, and OIG exclusion check in one view.
NPI Lookup →Who needs an NPI
Under 45 CFR § 162.410, any “covered healthcare provider” that transmits health information electronically in standard transactions must obtain an NPI. This covers:
- Physicians (MD, DO) and surgeons
- Nurse practitioners, physician assistants, clinical nurse specialists
- Dentists, oral surgeons, orthodontists
- Chiropractors, physical therapists, occupational therapists
- Psychologists, licensed clinical social workers, counselors
- Optometrists, audiologists, speech-language pathologists
- Pharmacists and pharmacies
- Hospitals, outpatient clinics, ambulatory surgical centers
- Home health agencies, hospice providers, skilled nursing facilities
- Group practices and health systems (Type 2)
Providers who do not bill Medicare or Medicaid and do not transmit electronic health information (rare in modern practice) are technically exempt, but most obtain an NPI anyway because commercial payers also require it.
Why NPIs matter for patients and researchers
Because an NPI is permanent and public, it is the most reliable way to uniquely identify a healthcare provider across datasets. A patient checking a provider's credentials can look up their NPI on NPPES to confirm their name, specialty, and practice address — and then cross-check against the OIG exclusion list to see if they have been excluded from federal programs. Researchers and journalists use NPIs to join Medicare claims data to provider characteristics. Insurers use NPIs to process claims without ambiguity. The NPI is the anchor of the US healthcare provider identity graph.
Fonteum uses NPIs as the primary join key across its 23 federal source families — linking NPPES identity records to CMS PECOS enrollment, CMS MIPS quality scores, OIG exclusion history, and HRSA HPSA shortage area designations. Every provider profile at fonteum.com/providers/[npi] traces each displayed field to a specific source, date, and provenance record.
Frequently asked questions
- What is an NPI number?
- An NPI (National Provider Identifier) is a unique, permanent 10-digit number assigned to every US healthcare provider — individual clinicians, group practices, hospitals, and other organizations — by the Centers for Medicare & Medicaid Services (CMS). It was mandated by the Health Insurance Portability and Accountability Act (HIPAA) and is administered through the NPPES registry.
- Who needs an NPI?
- Any healthcare provider that transmits health information electronically in HIPAA-covered transactions is required to obtain an NPI. This includes physicians, dentists, nurse practitioners, chiropractors, therapists, pharmacies, hospitals, group practices, and home health agencies. Providers who bill Medicare or Medicaid are required to have an NPI regardless of how they submit claims.
- What does an NPI number look like?
- An NPI is always exactly 10 digits. The first digit is always 1 (for Type 1 individual providers) or 2 (for Type 2 organizational providers). The last digit is a Luhn check digit — a mathematical validation to catch transcription errors. Example individual NPI format: 1234567893. Example organization NPI: 1567891234.
- What is the difference between Type 1 and Type 2 NPIs?
- A Type 1 NPI is assigned to an individual healthcare provider — a single person such as a physician, nurse practitioner, or physical therapist. A Type 2 NPI is assigned to an organizational provider — a group practice, hospital, health system, pharmacy, or other entity that employs or contracts with individual providers. One organization can have multiple Type 2 NPIs for distinct locations.
- How do I find a provider's NPI number?
- The National Plan and Provider Enumeration System (NPPES) is the official free public registry. Search by name, specialty, city, or state at nppes.cms.hhs.gov. Fonteum also provides an NPI lookup tool at fonteum.com/tools/npi-lookup that returns NPPES record details, CMS PECOS enrollment status, and OIG exclusion status in one view.
- Is an NPI the same as a DEA number or state medical license?
- No. An NPI is a federal administrative identifier — it does not confer prescribing authority or licensure. A DEA (Drug Enforcement Administration) registration number authorizes a provider to prescribe controlled substances. A state medical license is issued by the state medical board and required to practice medicine in that state. Providers typically hold all three.
- Does an NPI expire or change?
- An NPI is permanent and does not expire. It stays with the provider for life, even if they move states, change employers, retire, or change specialties. Providers are required to update their NPPES record within 30 days of any change to their name, address, taxonomy code, or other enumerated information. NPIs are never reused after a provider is deactivated.
Related
- NPI meaning and common questions — what the number means, how it differs from other IDs, and what NPPES records contain.
- How to check an NPI — step-by-step guide to looking up, validating, and cross-referencing an NPI against federal registries.
- NPI lookup tool — search any US provider by NPI or name; returns NPPES, PECOS, and OIG records.
- OIG LEIE sanctions — look up whether a provider has been excluded from federal healthcare programs.
- County-level nursing-home staffing deserts — how NPI-linked staffing data reveals regional care access gaps.