How the sign is found
Your Western sun sign depends only on the day and month of birth, not the year. The calendar is divided into twelve ranges, each ruled by one sign and one of four elements:
if birthday falls within a sign's date range
then sign = that sign
element = Fire / Earth / Air / Water
The calculator compares your month and day against the standard boundaries and returns the matching sign, its element and its full date span.
Worked example
Someone born on 15 August:
Range check: 23 Jul – 22 Aug is Leo.
Sign: Leo ♌.
Element: Fire.
Cusp note: exact change dates can move by a day between years. A birthday on 22 or 23 August sits on the Leo–Virgo cusp; confirm with a precise birth date and time if it matters.
The four elements
Astrology groups the twelve signs into four elements that share broad temperament themes. Fire (Aries, Leo, Sagittarius) is bold and energetic; Earth (Taurus, Virgo, Capricorn) is grounded and practical; Air (Gemini, Libra, Aquarius) is intellectual and social; and Water (Cancer, Scorpio, Pisces) is emotional and intuitive.