How to Look Up an NPI Number?
Quick Answer
You can look up an NPI number for free using two primary methods: (1) The official NPPES NPI Registry at npiregistry.cms.hhs.gov, which provides basic provider directory information (name, address, specialty, taxonomy code), or (2) NPIxray at npixray.com, which provides the same directory information PLUS the provider's complete Medicare billing analysis including revenue benchmarks, E&M code distribution, care management gaps, and estimated missed revenue. Both tools are free and require no registration. The NPPES Registry supports search by NPI number, provider first/last name, specialty, state, and city. NPIxray adds Medicare billing intelligence to every lookup, sourced from 1.175M provider records and 8.15M billing records in the CMS public dataset. As of 2026, there are over 8.2 million active NPI numbers registered in the NPPES system. Source: NPIxray analysis of 1.175M Medicare providers and 8.15M billing records.
Method 1: NPPES NPI Registry (Official)
The National Plan and Provider Enumeration System (NPPES) NPI Registry is the official government database maintained by CMS. It is available at npiregistry.cms.hhs.gov and provides free public access to all registered NPI numbers. You can search by: NPI number (10-digit identifier), provider first and last name, organization name (for Type 2 NPIs), taxonomy description (specialty), state and city, and ZIP code.
The NPPES Registry returns: provider name, NPI number, NPI type (1 or 2), enumeration date, practice address(es), mailing address, taxonomy/specialty classification, and associated organization information. It is updated weekly and is the authoritative source for NPI directory information. However, it does NOT include any billing or revenue data — it is purely a directory lookup.
Method 2: NPIxray (Enhanced Lookup with Billing Data)
NPIxray provides an enhanced NPI lookup that includes everything in the NPPES Registry PLUS detailed Medicare billing analysis. When you enter an NPI on NPIxray, you get: all standard NPPES directory information, the provider's E&M code distribution compared to specialty benchmarks, estimated missed revenue from undercoding, care management program adoption status (CCM, RPM, BHI), AWV completion rate, total Medicare payments and service counts, and a personalized revenue gap analysis.
This additional layer of billing intelligence makes NPIxray the preferred tool for practice managers, administrators, and providers who want to understand not just who a provider is, but how they bill and where they may be leaving revenue on the table. The data comes from the CMS Medicare Physician & Other Practitioners public dataset, which covers 1.175M providers and 8.15M billing records.
Looking Up an NPI by Provider Name
If you know the provider's name but not their NPI, both NPPES and NPIxray allow name-based searches. Tips for effective name searches: use the provider's legal first and last name (not a nickname or shortened form), add the state to narrow results (common names may return hundreds of matches), adding the city further narrows results, and for organization NPIs, search by the legal business name.
Common reasons for failed name searches include: the provider registered under a different name (maiden name, legal name change), spelling variations (particularly for non-English names), the provider has not yet applied for an NPI, or searching for an individual's name when the NPI is registered to their organization.
Using NPI Lookup for Due Diligence
NPI lookups serve several important functions beyond simple directory searches. Credentialing and enrollment: verify provider information during payer enrollment and hospital credentialing. Referral verification: confirm that a referring provider has a valid, active NPI before processing referrals. Billing accuracy: ensure the correct NPI is being used on claims (wrong NPI is a common cause of claim denials). Competitive analysis: practice managers use NPIxray to compare their billing patterns to nearby competitors and identify areas where they are underperforming.
For practice administrators, NPIxray's revenue analysis turns a simple NPI lookup into a strategic planning tool. You can scan any competitor, colleague, or newly hired provider to understand their billing patterns and benchmark against your own practice.
NPPES API for Developers
For applications that need programmatic NPI lookups, CMS provides a free API: GET https://npiregistry.cms.hhs.gov/api/?version=2.1&number={npi}. This API requires no authentication or API key and supports all the same search parameters as the web interface. It returns JSON data including provider name, addresses, taxonomies, and other enumeration details.
Rate limits are generous (not officially published but generally supports moderate query volumes). The API is commonly used by healthcare IT applications, billing systems, and credentialing platforms. NPIxray also provides an API for developers who need NPI lookup with billing data included — see npixray.com/api-docs for documentation.
Frequently Asked Questions
Is NPI lookup free?
Yes. Both the NPPES NPI Registry and NPIxray offer free NPI lookups with no registration required. The NPPES Registry provides directory information, while NPIxray adds Medicare billing analysis at no cost.
Can I look up anyone's NPI number?
Yes. NPI numbers are public information. Any person can look up any provider's NPI number, including their practice address, specialty, and (through NPIxray) their Medicare billing patterns. This data is public by law under HIPAA's Administrative Simplification provisions and the Freedom of Information Act.
How current is NPI Registry data?
The NPPES NPI Registry is updated weekly. Providers are required to update their information within 30 days of any changes. However, some providers are slow to update, so address or practice information may occasionally be out of date. Medicare billing data on NPIxray is updated based on the latest CMS data release cycle.
See Your Practice's Specific Numbers
Enter any NPI number to instantly see missed revenue from E&M coding gaps, CCM, RPM, BHI, and AWV programs — based on real CMS Medicare data.
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