What is a taxonomy code on an NPI application?

Answer: A taxonomy code is a 10-character code from the NUCC Health Care Provider Taxonomy that tells CMS your profession and specialty: 225700000X is Massage Therapist, 101YM0800X is Counselor, Mental Health, 363LF0000X is Nurse Practitioner, Family. You pick at least one on the NPI application and can list more. SimpleNPI picks it for you from your license type.

How the code is built

The NUCC taxonomy groups providers by type (Behavioral Health, Nursing Service, Chiropractic and so on), then by classification (Counselor, Registered Nurse) and specialization (Mental Health, Psychiatric/Mental Health). Every code ends in X. The set is updated twice a year by the National Uniform Claim Committee; the current version is 26.1.

Picking the right one

Choose the code that matches your license, not your aspirations. Payers read it when they credential you and when they decide whether a claim is within your scope. If your profession has a specialization that matches your license (Clinical Social Worker, Family NP), use it rather than the general code. You can list several and mark one primary. Browse by profession at NPI by profession or search every code at the taxonomy code lookup.

Changing it later

Free, in NPPES, any time. Students start with 390200000X and switch at licensure; an RN who becomes an NP adds the NP code; an LMSW who becomes an LCSW switches from Social Worker to Social Worker, Clinical.

Need an NPI?

Option 1 · Free · Easiest

SimpleNPI files it for you

One short form: name, license, contact, address, identity and an e-signed authorization. About 3 minutes, no CMS account to create.
A person checks your license and address, then files the application with CMS under your signed authorization.
Your NPI arrives by email and text, with all the documentation, usually within 10 minutes. Filed after midnight Eastern? It issues around 6 am Eastern.

Usually within 10 minutes after the form is complete.

Start the free application

Option 2 · Free

Apply yourself at NPPES

Create an Identity & Access account at nppes.cms.hhs.gov.
Choose Apply for an NPI for myself, Individual (Type 1).
Enter identity, addresses, taxonomy code and license number, then certify and submit.

Usually a few business days; often minutes when the Social Security match passes.

Go to NPPES

Written by Ammon Hardin, LMT, who grew a massage practice to ten locations, built a veteran therapy network, and credentialed a large number of providers along the way. Updated Tue Oct 27, 2026. Free to read, free to use; SimpleNPI files NPI applications for free.