Verify an NPI Number
Validate an NPI and see which provider it belongs to
Enter a 10-digit NPI to verify it. This tool confirms two things at once: that the number is structurally valid using the official Luhn check digit, and that it is actually registered in the NPPES registry, and then shows you the provider the NPI is assigned to.
Structural check is instant; registration and provider details come from the public NPPES registry.
10 numeric digits. The tool checks both the math and whether the NPI is registered.
Use this tool to verify any National Provider Identifier. It runs two checks: first it confirms the number is structurally valid using the ISO Luhn check-digit formula that NPPES uses, then it confirms the NPI is actually registered and shows you the provider it belongs to. A number can be mathematically valid but unassigned, so both checks matter.
How to verify an NPI number
Enter the 10-digit NPI in the box above and select Verify NPI. If the number is valid and registered, you will see the provider's name, specialty, and practice location, with a link to the full profile. If it is not valid, you will see exactly why, along with the check-digit math.
What makes an NPI number valid?
A valid NPI is exactly 10 numeric digits, where the first 9 digits carry the identity and the 10th is a check digit calculated with the Luhn "double-add-double" formula. If the check digit does not match, the number is not a valid NPI.
Can an NPI be valid but still wrong?
Yes. A number can pass the check-digit math yet never have been assigned to anyone. That is why this tool also checks the NPPES registry: a true verification confirms both that the number is structurally valid and that it belongs to a real, registered provider.
Is verifying an NPI the same as confirming the provider is legitimate?
Not entirely. Verifying an NPI confirms the identifier is valid and registered, but it does not confirm licensure, Medicare enrollment, or current practice details. To check Medicare enrollment, use the PECOS lookup; to review full provider details, open the NPI profile.
Do I need an account to verify an NPI?
No. This tool is free and requires no account. It reads only public information from the NPPES registry.
How the NPI check digit is calculated
The NPI uses the ISO standard Luhn algorithm to guard against typos. Using the example NPI 1134296023, here is how the final check digit is derived from the first nine digits.
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Step 1: Double every other digit
Starting from the rightmost of the first nine digits, double the value of alternate digits. For 1‑1‑3‑4‑2‑9‑6‑0‑2 this doubles the 1st, 3rd, 5th, 7th and 9th digits, giving: 2, 1, 6, 4, 4, 9, 12, 0, 4.
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Step 2: Add the digits, plus the constant 24
Add together the individual digits of those results (splitting any two-digit number, so 12 becomes 1 + 2), then add the constant 24 that NPPES uses for the 80840 prefix. That is 2+1+6+4+4+9+1+2+0+4 + 24 = 57.
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Step 3: Round up to find the check digit
Subtract the total from the next multiple of ten. The next multiple of ten above 57 is 60, so the check digit is 60 − 57 = 3. Because that matches the 10th digit of 1134296023, the NPI is valid.
