Your Sun sign is the sign of the zodiac the Sun was passing through on the day you were born. It's the headline placement, the one people mean when they ask "what's your sign?" In the language of astrology, the Sun represents your core self: the energy you radiate, the part of you that's most visibly you across moods, relationships, and seasons of life.
Enter your birth date and we'll compute it from the Sun's actual position against the tropical zodiac. Date alone is enough; time and place are only needed if you also want the rest of the chart (Moon, Rising, planets, and houses). Everything runs in your browser, your birth data is never stored on our servers.
Why date alone is enough
The Sun moves through the zodiac at roughly one degree per day, so the Sun sign almost never changes within a 24-hour window. The exception is the cusp days, the day the Sun crosses from one sign to the next (around the 19th–23rd of each month). On a cusp day the time and year can swing the result by one sign. The calculator handles that exactly, using the Sun's true ecliptic longitude rather than fixed date ranges.
What your Sun sign actually says
The Sun governs your sense of identity, your essential motivations, and the qualities you grow into over a lifetime. It's not your personality in full (that's the whole chart's job), it's the spine. A Leo Sun and a Scorpio Sun can both be introverted, ambitious, generous, but the flavor of those traits, the why behind the choices, runs through the Sun.
For the rest of the picture, our birth chart calculator layers in your Moon, Rising, and personal planets.
Key takeaway
Your Sun sign is the zodiac sign the Sun occupied on your birth date. It represents your core identity. Date alone is enough to compute it accurately, time and city only matter if you want the full chart.
Source: Astronomy Engine (geocentric ephemeris) for the Sun's ecliptic longitude
Examples
Born September 5, 1985
- Birth date 1985-09-05
- Birth time (optional)
- Birth location (optional for Sun sign) Cleveland, Ohio, United States
September 5 lands well inside the Virgo Sun range (the Sun is in Virgo from roughly August 23 to September 22). No time or location needed, the Sun's position on that date is unambiguous.
Born March 20, 2000 (a cusp date)
- Birth date 2000-03-20
- Birth time (optional) 08:00
- Birth location (optional for Sun sign) London, United Kingdom
March 20 is right on the Pisces / Aries cusp: in 2000 the Sun crossed into Aries at about 07:35 UT, so a London birth at 08:00 local time (also UT in March, before BST) is just barely Aries. Born a few hours earlier the same day and you'd be Pisces; this is why cusp births need the time, not just the date.
Frequently asked questions
I was born on a cusp date. Which sign am I?
On the day the Sun changes signs (around the 19th–23rd of each month), the answer depends on the exact moment of birth and the year. The Sun's position shifts very slightly year to year because of the Gregorian leap cycle. This calculator computes the Sun's true ecliptic longitude for your specific date and time, so a cusp birth gets the actual sign, not a fixed lookup-table guess. If your time is unknown and the date is right on the boundary, the result for an early- or late-day birth may differ; try both 00:01 and 23:59 to see whether you straddle.
Does the Sun sign mean the same thing in every astrology tradition?
We use the tropical zodiac, the system most Western astrology and every major newspaper horoscope uses. It's tied to the seasons, not to the visible constellations. Sidereal astrology (used in Vedic traditions) is tied to the actual constellations and runs about 24° behind tropical, so a tropical Aries is a sidereal Pisces in most cases. Both systems are internally consistent; they're answering slightly different questions. If you're new to astrology and most of what you've read is Western, tropical is the system you want.
My Sun sign doesn't feel like me. Did I get it wrong?
Almost certainly not, the Sun sign is the easiest placement to compute and the hardest to mistake. What's more likely is that another placement is louder in your day-to-day. Your Moon sign governs your inner emotional life and Rising sign governs how strangers perceive you, and either can dominate the felt sense of "who I am." Many people identify more with their Moon or Rising than their Sun. Run the full birth chart calculator and you'll usually spot which placement is doing the heavy lifting.
How is the Sun sign different from a horoscope?
Your Sun sign is fixed, it's the sign the Sun was in when you were born and it never changes. A daily horoscope is a transit reading, based on where the planets are right now relative to your Sun sign. Most newspaper horoscopes only use the Sun, which is why two Geminis with very different Moons and Risings can read the same horoscope and feel it lands totally differently. For more grounded daily-scale astrology, the Moon and Rising signs matter at least as much.