Free Billing Tool
Free NPI Validator
Check whether a 10-digit National Provider Identifier has the correct numeric format and CMS/Luhn check digit. The calculation runs locally in your browser.
Validate an NPI
Enter a 10-digit NPI. Spaces and hyphens are ignored.
NPI result
What does an NPI checksum validator check?
A National Provider Identifier is a 10-position numeric identifier used in HIPAA administrative transactions. CMS specifies a modulus-10 Luhn “double-add-double” check digit. For NPI calculations, the check digit is calculated as though the health-card prefix 80840 precedes the identifier.
This validator checks the 10-digit format and that mathematical check digit. It is useful for catching mistyped NPIs before you place them on a CMS-1500 claim or an 837P electronic claim.
What a valid result does not prove
A checksum-valid NPI is not the same thing as an active, correctly matched, licensed, enrolled, credentialed, or payable provider. The tool does not look up provider identity, taxonomy, enrollment, sanction, or payer status. For identity and registry information, use the official NPPES NPI Registry. For the checksum method itself, see the CMS NPI Check Digit Requirements.
Where NPIs appear in professional claims
CMS-1500 and 837P professional claim workflows can contain billing, rendering, referring, ordering, supervising, service-facility, or other provider identifiers depending on the claim and payer rules. A correct checksum is only one part of claim quality.
Check the rest of the professional claim
Use the CMS-1500 Claim Checker for a broader pre-submission review, or use the 837P software when you need to create a professional electronic claim file.
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