NPI Lookup: How to Find a Doctor's NPI Number

What is an NPI number?

An NPI (National Provider Identifier) is a 10-digit number that identifies a health care provider in the United States. The Centers for Medicare & Medicaid Services (CMS) issues it through the National Plan and Provider Enumeration System (NPPES). CMS describes it as an intelligence-free identifier: the digits do not encode the provider's state, specialty or anything else. The last digit is a check digit that catches many typing mistakes.

Providers who send standard electronic transactions, such as insurance claims, must have an NPI, and many other providers get one too. The number stays the same when a provider moves, changes jobs or adds a specialty. There are two types:

Type 1 (individual): a person who provides care, such as a physician, dentist, nurse practitioner, pharmacist or physical therapist. Sole proprietors are Type 1. An individual can have only one NPI.
Type 2 (organization): a hospital, group practice, clinic, pharmacy, laboratory, nursing home or similar entity. An organization can hold more than one NPI for its different parts, so one hospital system may have several.

A provider who works through their own corporation or LLC may have both: a Type 1 NPI for themselves and a Type 2 NPI for the business.

How to do an NPI lookup in the NPPES NPI Registry

The official place for an NPI lookup is the NPPES NPI Registry. It is free and needs no account. According to CMS, it is updated daily and shows provider data that is public by law.

Open the NPI Registry search page.
If you have the number, enter all 10 digits in the NPI number field and search. This is the fastest and most exact NPI number lookup.
If you do not have it, choose whether you are looking for an individual or an organization.
For a person, enter the last name and, only if you are sure of it, the first name. For an organization, enter part of its name.
Add the state, and a city or ZIP code if the list is long.
Open the record that matches and compare its practice address and specialty with what you already know.

You can run the same kind of search in ASL Doctor Search, described near the end of this guide.

How to find a doctor's NPI number by name, state, specialty or ZIP

Most searches start with a name. To find a doctor's NPI number without the number in hand, combine a few details instead of typing everything you know. One extra field with a misspelling can hide the right record.

Name: start with the last name and the state, and add the first name only if there are too many results. Try the formal first name (Robert, not Bob), a former last name and, for two-part surnames, each part on its own.
State and city: use the state where the provider practices, not where you live, and add a city to shorten the list.
Specialty: enter a taxonomy description such as Family Medicine or Pediatrics to tell apart two providers with the same name.
ZIP code: a practice ZIP narrows results quickly, but it can drop a provider whose record lists a different office. Remove it if the search comes back empty.

Sometimes the easiest route is to ask. Practices share their NPI routinely with health plans and other providers that need it for billing, so the billing office can usually tell you. Referral paperwork and claim forms often show it as well.

How to read an NPI number lookup result

Each field in an NPI record answers a different question:

NPI and type: the 10-digit number and whether it belongs to an individual (Type 1) or an organization (Type 2).
Status: whether the number is active. CMS advises against using a deactivated NPI in claims and other standard transactions.
Enumeration date: the date the NPI was issued. It is not a license date or the date the provider started practicing.
Primary practice address: where the provider reports seeing patients. The mailing address is often a billing office or a post office box.
Taxonomy: the specialty the provider selected, shown as a 10-character code and a description from the Health Care Provider Taxonomy code set maintained by the NUCC. For example, 207Q00000X is Family Medicine. One taxonomy is marked as primary.
License number and state: often listed beside the taxonomy. It is what the provider reported, not a sign that the license is current.
Other identifiers and last update: some records list other health plan identifiers, and many show when the record was last updated.

Practice location vs. mailing address in an NPI lookup

Every NPI record has a mailing address and a primary practice address. They can be the same, but they answer different questions. The mailing address is for correspondence and may be a billing office, a headquarters or a post office box. The primary practice address is the practice location the provider designated as primary; the CMS NPI application form asks providers with more than one location to pick one.

Other offices can appear as secondary practice addresses. The registry's record page lists them under Secondary Practice Address(es), and CMS publishes them in its downloadable NPI data as a separate Practice Location Reference File of non-primary locations. Not every provider lists them, so a record may show one office for someone who works at several.

How to use the addresses:

To find where a provider sees patients, start with the primary practice address, check any secondary ones and call the office to confirm. The results list shows only the primary practice address and its phone number.
When a city, state or ZIP search misses a provider, the match may be on another address. The registry's Address Type menu can limit a location search to primary or secondary locations; left on Any, a search can also match the mailing address.
Telehealth-only providers may show an unusual practice address. CMS allows a post office box as the practice location only for an individual provider with no physical location other than a home, such as one who works only by telehealth.

If you are the provider, update your practice locations and mailing address in NPPES when they change. The CMS form notes that if your record does not match what insurers have on file, they may have trouble recognizing you.

Common NPI lookup problems

A common name returns dozens of matches. Add the state, city and specialty, then compare the practice address with the referral or appointment letter. If two records still look alike, call the office and ask for its NPI.
The provider moved. The NPI does not change, but the address on the record may lag behind. Search by name and the new state, and check the last-updated date. Federal rules give covered providers 30 days to report changes, yet records still fall behind.
The number returns nothing. Recheck all 10 digits; a single wrong digit usually fails the check digit. If the digits are right, the number may have been deactivated. For deactivated NPIs, CMS discloses only the number and the deactivation date, and it publishes a monthly deactivation file.
An organization shows several NPIs. Hospitals and groups can hold separate NPIs for different locations or services. Match the address and taxonomy to the location you deal with, and ask the billing office which NPI belongs on a claim.

What an NPI lookup does not prove

An NPI is an identifier, not a credential. The registry itself notes that issuing an NPI does not ensure a provider is licensed or credentialed. An active record means a provider registered a number and that the registry holds whatever they last reported.

License: check with the licensing board in the state where the provider practices. For physicians, the Federation of State Medical Boards offers DocInfo, which draws on state board data.
Board certification: a taxonomy is a category the provider chose. Ask the specialty board that certifies the provider.
Insurance: call your plan or use its directory, and confirm with the office before your visit.
Medicare enrollment: enrollment is a separate process, and updating an NPI record does not update it.
DEA registration: a DEA number is a different identifier. Registration questions go to the DEA Diversion Control Division.
Quality: nothing in the record rates care, outcomes or disciplinary history.

Privacy and etiquette when you look up a provider

NPPES data is public by design, and CMS says a provider with an active NPI cannot opt out of the published data. That openness exists so claims and referrals work, so use it for that kind of task.

Contact providers through their practice. Some individual providers list an address that is also their home; do not show up there.
Never use another provider's NPI on a claim, prescription or form they did not authorize. That can be fraud.
Keep patient details out of the search. An NPI lookup never needs a patient's name, date of birth or diagnosis.
If you are the provider and your record is wrong, update it in NPPES.

Where ASL Doctor Search fits

ASL Doctor Search is a free, bilingual search of the public federal provider registry, with complete English and Spanish interfaces and no account. It accepts partial names, and when a search finds nothing it retries with partial-name matches and says so on the results line. You can filter by specialty, city, state, ZIP and provider type, show only active records, and sort by distance from a starting ZIP, up to 250 miles.

Distance is approximate and filters the records your search already matched, so pair it with a city or state. An exact 10-digit lookup checks the number's check digit on your device before anything is sent. A separate DEA tool checks only a DEA number's structure and check digit, also on your device; a pass says nothing about whether a registration is active.

It is independent, not affiliated with CMS, HHS or the DEA, and not a verification service: an active record is not proof of a current license, board certification, accepted insurance or quality of care. See how ASL Doctor Search works.

Frequently asked questions

Is an NPI lookup free?

Yes. The NPPES NPI Registry from CMS is free and needs no account. Other lookup sites repackage the same public data, so there is no need to pay for a basic NPI lookup.

How do I find a doctor's NPI number?

Search the NPI Registry by last name and state, then narrow by city, ZIP or specialty. If several records match, compare the practice address, or ask the practice's billing office for its NPI.

What is the difference between the practice location and the mailing address in an NPI lookup?

The primary practice address is the main practice location the provider reported. The mailing address is for correspondence and is often a billing office or post office box. Some records also list secondary practice addresses for other offices.

Does a doctor's NPI number ever change?

No. An individual keeps one NPI for life, even after moving or changing specialties. A number can be deactivated, for example when a provider dies or an organization closes, and in some cases it can be reactivated.

Does an NPI number lookup show whether a doctor is licensed?

No. A record may list a license number the provider reported, but an NPI does not show that a license is current. Check with the state licensing board where the provider practices.

Is an NPI the same as a DEA number or a tax ID?

No. The NPI identifies a provider in health care transactions, a DEA registration number relates to prescribing controlled substances, and a tax ID is issued by the IRS. They are separate numbers from separate agencies.

Can I do an NPI lookup in Spanish?

The official NPI Registry is in English. ASL Doctor Search searches the same public registry with complete English and Spanish interfaces.

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NPI Lookup: How to Find and Read a Doctor's NPI Number