Identity
Your Sun sign
The Sun marks the center of the chart: vitality, purpose, and the qualities you learn to express with increasing confidence.
Calculate your Sun signSun Moon Rising Calculator
Find your Big Three astrology signs from your birth date, local birth time, and birthplace. See the tropical positions of your Sun, Moon, and Rising sign without sending your birth details away.
- Exact tropical positions
- Honest unknown-time results
- Private browser calculation
Read the three angles
What your Big Three means
Your Big Three is a compact way to begin reading a birth chart. Each placement answers a different question, so no single sign has to explain everything about you.
Inner life
Your Moon sign
The Moon describes emotional rhythm, instinctive reactions, and what helps you feel settled when no one else is watching.
Calculate your Moon signFirst impression
Your Rising sign
The Rising sign is the zodiac sign meeting the eastern horizon at birth. It frames first impressions and sets the orientation of the chart.
Calculate your Rising signAccuracy before certainty
Why your birth time matters
The Rising sign changes as Earth turns, so it depends on the exact local time and birthplace. Without a supported time, ChartOdyssey leaves Rising unavailable instead of inventing an answer.
Understand birth-time accuracySun usually stays stable
The calculator checks the complete local day rather than relying on date ranges.
The Moon can cross a boundary
If two signs are possible that day, both remain visible in the result.
Rising needs the clock
Exact time and place are required to calculate the eastern horizon.
Continue exploring
Go beyond your Big Three
The ChartOdyssey color system
Turn your chart into color
Combine your Sun, Moon, Rising, and Venus placements into an original four-color birth chart palette. Your Big Three remains the foundation; Venus adds a fourth color for taste and attraction.
SunMoonRisingVenus
Private by construction
Your birth details stay in this browser
ChartOdyssey matches the city and timezone locally, then calculates tropical placements in your browser. Your birth date, time, city, timezone, latitude, and longitude are not sent to analytics or an external astrology calculation service.
Big Three questions
Before you calculate
What are the Sun, Moon, and Rising signs?
They are the three placements commonly called your Big Three. The Sun describes your central identity, the Moon reflects emotional needs and instinctive responses, and the Rising sign describes the zodiac sign on the eastern horizon when you were born.
How do I calculate my Big Three?
Enter your birth date, local birth time, and birthplace. ChartOdyssey converts that local moment with the matched IANA timezone and calculates the tropical positions in your browser.
Can I calculate my Big Three without a birth time?
You can still check the Sun and, on many dates, the Moon. The Rising sign requires an exact supported birth time, so ChartOdyssey leaves it unavailable instead of guessing.
Why can the Moon result be uncertain?
The Moon moves quickly and can cross into another zodiac sign during one local day. When no birth time is available, the calculator checks the day boundary and shows both possible signs when necessary.
Are my birth details uploaded?
No. Your birth date, time, city, timezone, latitude, and longitude stay in this browser and are not sent to analytics or an external calculation service.