Find NIC Number Structure from Date of Birth
Enter a date of birth and gender to see the NIC day-of-year code, year prefix, and format structure for both old and new Sri Lankan NIC numbers.
Day-of-Year Code
166
Old Format Prefix
90166
+ 4 serial digits + V/X
New Format Prefix
1990166
+ 5 serial digits
Weekday
Friday
Gender Code
Male (1–366)
Leap Year?
No
Max Day Code
365
Note: The serial digits (last 4 or 5) are unique per person and assigned by the Department for Registration of Persons. No public tool can generate a complete NIC number from a birthday alone.
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How the DOB-to-NIC Calculation Works
Calculate the day of the year. Count how many days have passed since January 1 of the birth year. January 15 = day 15. June 15 = day 166 (or 167 in a leap year).
Add 500 for females. The DRP uses a +500 offset for female NICs. A female born on day 166 gets code 666. This lets one 3-digit field encode both birthday and gender.
Combine with the year. Old format: 2-digit year + day code. New format: 4-digit year + day code. The remaining digits are a unique serial assigned by DRP — we cannot generate those.
DOB to NIC — Frequently Asked Questions
No. A date of birth and gender only determine the first 5 digits (old format) or 7 digits (new format). The remaining serial digits are unique per person and assigned by the Department for Registration of Persons (DRP). No public tool can generate a full NIC from a birthday alone.
The day-of-year code is a 3-digit number encoding both birthday and gender. For males, it's the actual day number (001–366). For females, 500 is added (501–866). January 15 is day 015 for a male and 515 for a female.
Everyone born on the same date with the same gender shares the same NIC prefix. The DRP uses a 4-digit (old) or 5-digit (new) serial number to distinguish individuals born on the same day.