What is an NPI number?
Updated June 19, 2026
An NPI (National Provider Identifier) is the unique 10-digit number that identifies a health care provider in the United States. It was introduced under HIPAA and is issued by the Centers for Medicare & Medicaid Services (CMS) through the National Plan and Provider Enumeration System (NPPES). If a provider bills insurance — and most who don’t still carry one — they have an NPI.
The format: 10 digits and a check digit
An NPI is exactly ten digits. The first nine identify the provider; the tenth is a check digit calculated with the Luhn algorithm (using the industry prefix 80840), which lets software catch typos. Crucially, the NPI carries no embedded meaning — it doesn’t encode specialty, state, or anything else. To learn anything about a provider you have to look the number up.
Type 1 vs. Type 2 NPIs
| Type | Who it’s for | Examples |
|---|---|---|
| Type 1 | Individual providers | Physicians, nurse practitioners, dentists, therapists, pharmacists |
| Type 2 | Organizations | Hospitals, group practices, pharmacies, labs, imaging centers |
Who needs an NPI?
Any provider covered by HIPAA who transmits health information electronically — essentially anyone who bills Medicare, Medicaid, or commercial insurance — must have an NPI. There are more than 8 million active NPIs across individuals and organizations.
How do you get one?
Applications are free through NPPES at nppes.cms.hhs.gov. Once issued, the number is the provider’s for life.
Is an NPI public? Does it change?
Yes, NPIs and their associated registration details are public information (disclosable under the Freedom of Information Act). And no — an NPI is permanent. It survives a move, a name change, or a change of specialty, and it is never reassigned to someone else.
NPI vs. other provider identifiers
The NPI answers who. It is not the same as a taxonomy code, a PECOS Medicare-enrollment record, or a CLIA lab certificate — those answer different questions. To look up any NPI in plain English, type a number, a name, or something like “pediatricians in Houston, TX” into drfind.
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Frequently asked questions
How many digits is an NPI?
Ten. The tenth digit is a check digit, so a valid NPI is exactly 10 numbers with no letters.
Is an NPI the same as a Medicare number or tax ID?
No. The NPI only identifies the provider. Medicare enrollment (PECOS) and tax IDs are separate systems.
Can a provider have more than one NPI?
An individual should have exactly one. A person who also owns a practice may hold a Type 1 (themselves) and a Type 2 (the organization).
Do NPIs ever get reused or changed?
No. An NPI is permanent and is never reassigned, even after a provider retires.