Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Calvin Williams
Social Worker in Seattle, WA · enumerated 2026.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1265350995
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Registry record
Entity type Individual (Type 1)
Name Calvin Williams
Sex Male
Practice address 400 N 34th St Ste 320, Seattle, WA, 98103
Phone (206) 385-7864
Enumeration date Jul 9, 2026
Last updated in NPPES Jul 9, 2026
Taxonomy & licenses
104100000X Social Worker Behavioral Health & Social Service Providers · License SWIA.SC.70134673 (WA) Primary
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.
Frequently asked questions
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.
What specialty is Calvin Williams?
Calvin Williams is registered in NPPES with the primary taxonomy of Social Worker. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Other providers at this practice address
Browse all → Wesley Weidle Physician Assistant · Seattle, WA NPI 1689182529 Dominique Savage Mental Health Counselor · Seattle, WA NPI 1104420678 Katherine Hamilton Social Worker · Seattle, WA NPI 1821989468 Carmen Valenzuela Social Worker · Seattle, WA NPI 1225929888 Abigail Staley Mental Health Counselor · Seattle, WA NPI 1841168796 Riley Evans Mental Health Counselor · Seattle, WA NPI 1437076395
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-07-09.