What is an NPI number?
A National Provider Identifier, or NPI, is a unique 10-digit number that identifies a health care provider in the United States. It's how insurers, Medicare, Medicaid, pharmacies and other providers know exactly who provided or billed for care.
Who has one
Under HIPAA, every health care provider who sends health information electronically for billing, eligibility checks or referrals must have an NPI and use it. That covers nearly every doctor, nurse practitioner, physician assistant, dentist, pharmacist, therapist, psychologist, chiropractor and optometrist, and nearly every hospital, clinic, group practice, pharmacy, lab, home health agency, ambulance company and medical equipment supplier. Many providers who don't bill electronically get one anyway, because employers and insurers ask for it.
Health plans and clearinghouses don't get NPIs; the number is only for providers.
What the number means
Nothing, on purpose. The NPI is "intelligence-free": the digits don't encode the provider's specialty, state or anything else. The first nine digits are assigned in sequence and the tenth is a check digit, calculated with the Luhn formula used for credit card numbers, so most typos produce an invalid number. NPIs start with 1 or 2.
It doesn't change
A provider keeps the same NPI for life: through moves, new jobs, name changes and new licenses in other states. If an NPI is deactivated, it's never given to anyone else.
Two types
Type 1 NPIs are for individual people. Type 2 NPIs are for organizations such as hospitals, group practices and pharmacies. A doctor can have a Type 1 NPI for herself and work for a practice that bills under its own Type 2 NPI. More on the two types.
What an NPI doesn't tell you
An NPI shows that a provider applied for and received a number. It doesn't prove they're licensed, board-certified, in your insurance network or in good standing. Check licenses with the state licensing board, and network status with your insurer.
Who issues it
The Centers for Medicare & Medicaid Services (CMS) issues NPIs through the National Plan and Provider Enumeration System (NPPES). Getting one is free. How to apply.
How to look one up
Search by name or number on our home page, browse by specialty or by state, or use the official CMS NPI Registry. Both show the same public NPPES data; ours adds pages by specialty and city, and other providers at the same address.