39 years old now in 2025 - what year born?

Today, 19 December 2025 if a person is 39 years old now, what year was he born? See below:

If 39 years old, year of birth is:
1985 or 1986*

*It depends on whether he was born before or after 1 January 1986.

If now 39 years and his year of birth 1985 if he was born after 19 December 1985 until 31 december 1985 inclusively, and his year of birth is 1986 if he was born from 1 January 1986 to 19 December 1986.

Other examples:

If now 5 years, year of birth 2019 or 2020
If now 14 years, year of birth 2010 or 2011
If now 27 years, year of birth 1997 or 1998
If now 100 years, year of birth 1924 or 1925

HTML code:

BB code: