An NPI (National Provider Identifier) is a free, permanent 10-digit number that identifies a health care provider on insurance claims, prescriptions and referrals across the United States. It tells a health plan or pharmacy who the provider is. However, it is not a license, and it doesn’t show that a clinician is qualified, certified or in good standing.
What is an NPI number? Key facts
- One number per provider, for life. In other words, it stays the same when a clinician changes jobs, moves to another state or changes specialty.
- Two kinds. Type 1 NPIs are for individual people (doctors, nurses, therapists, pharmacists and others). Meanwhile, Type 2 NPIs are for organizations (hospitals, clinics, group practices, pharmacies, labs).
- Issued by the federal government through CMS’s National Plan and Provider Enumeration System (NPPES), at no cost.
- Public by law. As a result, the registry shows each provider’s name, practice address, phone, specialties and the state license numbers they reported.
- Self-reported. Providers enter their own details; however, the registry doesn’t verify them. Still, covered providers must report changes within 30 days.
- Scale. The November 2026 registry has about 7.5 million individuals and 2.0 million organizations with an active NPI and a U.S. practice address.
What an NPI is not
| Often confused with | What it actually is | Who issues it |
|---|---|---|
| Medical license | Permission to practice medicine in one state. A doctor practicing in three states holds three licenses but has one NPI. | Each state’s medical board |
| DEA registration | Permission to prescribe controlled substances, such as opioids and stimulants. | Drug Enforcement Administration |
| Board certification | Proof that a doctor passed a specialty board’s exams and keeps up its requirements. | Specialty boards (ABMS member boards for MDs, AOA boards for DOs) |
| Insurance network membership | A contract with a health plan. Having an NPI doesn’t mean a provider takes your insurance. | Each health plan |
| A quality rating | An NPI says nothing about skill, outcomes or complaints. | — |
What the number looks like
An NPI has 10 digits, such as 1234567893. In other words, the digits carry no meaning: they don’t encode a state, a specialty or a year. Also, the last digit is a check digit, calculated with the Luhn formula (the same method used for credit card numbers, with the prefix 80840 added before calculating), so claim systems catch most typing mistakes.
A short history
| Date | What happened |
|---|---|
| August 21, 1996 | HIPAA called for a single national identifier for health care providers. |
| January 23, 2004 | HHS published the final rule adopting the NPI. |
| May 23, 2005 | The rule took effect and providers could start applying. |
| May 23, 2007 | Most health plans, clearinghouses and providers had to use NPIs on standard electronic transactions. CMS allowed good-faith contingency plans until May 23, 2008. |
| September 4, 2007 | The public NPI Registry opened; the full downloadable file followed on September 12. |
| May 23, 2008 | Deadline for small health plans, and the end of all contingency plans. |
How fast doctors signed up
Overall, looking at the physicians practicing today, about half got their NPI before the May 2007 deadline:
| By this date | Share of today’s physicians who already had an NPI |
|---|---|
| End of 2005 (first 7 months) | 10% |
| May 23, 2006 (first year) | 21% |
| May 23, 2007 (compliance date) | 51% |
| May 23, 2008 (end of contingency plans) | 56% |
In fact, the busiest year was 2006, the year before the deadline. After the rush, new NPIs fell to about 240,000 in 2009 (individuals and organizations together), then climbed steadily to about 630,000 in 2025, as more nurse practitioners, therapists, counselors and other clinicians registered.
| Year issued | Individuals | Organizations |
|---|---|---|
| 2005 (from May 23) | 202,654 | 38,602 |
| 2006 | 911,597 | 272,954 |
| 2007 | 567,218 | 222,797 |
| 2008 | 238,133 | 95,516 |
| 2009 | 178,252 | 63,528 |
| 2010 | 193,876 | 63,615 |
| 2015 | 227,235 | 69,624 |
| 2020 | 353,079 | 73,761 |
| 2024 | 447,632 | 99,676 |
| 2025 | 518,563 | 112,081 |
Why many doctors’ NPI dates are 2005 to 2007
At the start, every doctor who was already practicing had to get an NPI. That is why 55% of the physicians in our data have an NPI date between 2005 and 2007, whether they started practicing in 1975 or 2004. In other words, an early NPI date only tells you the clinician was working by then. So it is not a license date, a graduation date or a sign of experience. In contrast, for doctors who trained after 2007, the NPI date is often close to the start of residency, when they first need the number to write prescriptions and order tests.
How the NPI is used
By doctors and other clinicians
- On every claim they send to Medicare, Medicaid and private insurers, as the provider who gave the care.
- On prescriptions, lab and imaging orders and referrals, as the ordering or referring provider.
- To enroll with Medicare and to join insurers’ networks.
By insurance companies and Medicare
- To match each claim to the right provider and pay the right party.
- For provider directories and network records. Before a clinician joins a network, the plan still checks the license, board certification and history separately (credentialing).
- Also, to spot unusual billing and fraud, since every claim from a provider carries the same number.
By pharmacies
- First, each pharmacy has its own organization NPI.
- In addition, pharmacy claims to drug plans carry the prescriber’s NPI. That is how Medicare can publish how often each clinician prescribes each drug.
By hospitals and health systems
- Typically, a hospital bills under its organization NPI. Moreover, large systems often have separate NPIs for parts of the organization, such as a lab or an outpatient clinic.
- Doctors employed by a hospital or group usually let it bill for their work, but their own NPI still appears on the claim as the clinician who gave the care.
By researchers, reporters and this site
Because the same number appears in Medicare’s prescribing and service data, in Open Payments (industry payments to clinicians) and in Medicare’s Care Compare, the NPI is what lets public datasets be joined. In fact, we build every doctor page on contact.doctor this way: the NPI links the registry details to Medicare services, prescriptions and industry payments for the same person.
What the public registry shows, and what it doesn’t
| Shown | Not shown |
|---|---|
| Name, credential (MD, DO, NP…) and sex | Social Security number, date of birth |
| Practice location and phone; mailing address | Home address (unless the provider uses it as a practice address) |
| Specialties (taxonomy codes), with one marked primary | Whether a license is current or has been disciplined |
| State license numbers, as the provider reported them | Board certification, training, malpractice history |
| Date the NPI was issued and last updated | Insurance networks, languages spoken, whether accepting new patients |
| For organizations: an authorized official’s name and title | Deactivated NPIs (removed from the public file) |
Because the registry is self-reported, addresses and phone numbers can be out of date. Therefore, call before visiting, and confirm a license with the state medical board.
Common questions
How do I find my doctor’s NPI?
First, search for the doctor by name, specialty and place on Find a doctor. Then each doctor page shows the NPI with their specialties, licenses and Medicare data. You can also find it on many bills, explanation-of-benefits statements and prescription labels.
Do nurses, therapists and pharmacists have NPIs?
Yes. In fact, any health care provider can get one, and those who bill insurers electronically must. For example, nurse practitioners, physician assistants, physical therapists, psychologists, counselors, dentists and pharmacists all commonly have NPIs.
Can an NPI change or be taken away?
A provider keeps the same NPI for life. However, NPPES can deactivate one, for example after a death, at the provider’s request, or when someone got or used an NPI fraudulently. A deactivated NPI disappears from the public registry. Later, NPPES can reactivate it.
Is it a problem that NPIs are public?
Sharing the NPI is the point: it appears on every claim and prescription. But because it is public, criminals sometimes use real providers’ NPIs to bill for care that never happened. If a bill or benefits statement lists a provider you never saw, report it to your insurer or, for Medicare, to 1-800-MEDICARE.
In addition, our FAQ answers more questions about doctors, licenses, Medicare data and doctor pay.
Sources
- Code of Federal Regulations, 45 CFR part 162, subpart D (standard unique health identifier for health care providers): eCFR
- HHS, Unique Identifiers FAQs (30-day update rule, taxonomy changes): hhs.gov
- CMS, NPPES data dissemination (public registry, September 2007; deactivated NPIs withheld): cms.gov
- CMS NPI contingency guidance, 2007, as summarized by Crowell & Moring
- Counts and the share of physicians with 2005–2007 NPI dates: contact.doctor analysis of the NPPES NPI file, November 2026 release (active NPIs with a U.S. practice address; physicians as defined on the Methodology page).
- Official lookup: CMS NPI Registry