Is the constellation calculated by the year of birth?

Constellations are usually determined according to the date of birth, not the year of birth.

For example, if a person's date of birth is 2 1 March, then his constellation should be Aries, regardless of the year of birth.

Constellations are divided according to the position of the sun in the ecliptic. Each constellation occupies about 30 degrees of the ecliptic, and the sun runs on this belt for about one month. So a person's horoscope is determined according to their date of birth, not the year of birth.