NPI Validation Tool

Enter the National Provider Identifier (NPI) Number to validate

NPI Validation Rules

The National Provider Indentifier (NPI) is 10-position all-numeric identification number assigned by the National Plan and Provider Enumeration System (NPPES) to uniquely identify a health care provider.

Characteristics of NPI numbers:

  • NPI numbers consist of 9 numeric digits followed by one numeric check digit, for a total of 10 numeric digits.
  • The NPI numbers check digit is calculated using the Luhn Formula algorithm for Modulus 10 "double-add-double".
  • NPI numbers are compatible with ISO identification card standards for a card issuer identifier.
  • NPI numbers have no embedded intelligence.
  • NPI numbers do not require translation before application of the check digit algorithm and thus uses the full ability of the check digit algorithm to detect keying errors.

How to calculate the NPI check digit?


Take the first 9 digits of the NPI number and double the value of alternate digits beginning with the rightmost digit.

Example NPI: 1134296023
1 x 2 = 2
3 x 2 = 6
2 x 2 = 4
6 x 2 = 12
2 x 2 = 4
3 - Check Digit


Sum the individual digits of the products resulting from step 1 to the unaffected digits from the original number and add a constant 24.

Sum plus constant: 2+1+6+4+4+9+1+2+0+4+24= 57


Subtract the total obtained in step 2 from the next higher number ending in zero, this is the check digit. If the number obtained in step 2 ends in zero, the check digit is zero.

Check Digit: 60- 57 = 3