Sun, Moon & Rising Sign Calculator
This sun moon rising sign calculator reveals your Big Three from your birth date, time and place, with degrees and meanings.
Formula & worked example
Formula: Sun and Moon longitudes come from astronomical series (Meeus); the Rising sign from local sidereal time, latitude and the obliquity of the ecliptic. Sign = ⌊longitude ÷ 30⌋.
Example: 1 January 2000, noon, London: Sun 10° Capricorn, Moon about 13° Scorpio, Rising about 24° Aries.
Method & source: Jean Meeus, Astronomical Algorithms (Sun ch. 25, Moon ch. 47); ascendant from local sidereal time. See how we test our calculators.
Next step: try exact age or days between two dates.
Your Sun, Moon and Rising Signs
A sun moon rising sign calculator finds the three placements astrologers call your Big Three. Your Sun sign is the zodiac sign the Sun occupied when you were born, your Moon sign is where the Moon was, and your Rising sign (ascendant) is the sign on the eastern horizon at that moment.
Together they describe your core identity, your emotional inner world and the way you come across to others – which is why they give a much fuller picture than a Sun sign alone.
Calculating the Big Three From Birth Details
Enter your name, birth date, birth time and birth city. The calculator converts your local time to universal time using the time zone of your birthplace.
- Sun sign: Calculated from the Sun’s ecliptic longitude on your birth date and time.
- Moon sign: Calculated from a lunar longitude series, since the Moon moves about 13° a day.
- Rising sign: Calculated from sidereal time, your latitude and longitude and the obliquity of the ecliptic.
- Degrees and qualities: Each placement shows its degree, element and modality.
- Borderline warning: If a placement is very close to a sign boundary you are told to double-check your birth time.
Calculations use the tropical zodiac and run in your browser – your birth details are not sent anywhere except a city search for coordinates.
Why Your Big Three Matter
Astrology is a tool for reflection, and the Big Three are the most popular starting point for exploring yourself.
- Understand why you don’t fully match your Sun sign description.
- Explore the difference between your public self and your private self.
- Compare Big Three combinations with friends and partners.
- Get a starting point for a full birth chart reading.
- Enjoy a fun, reflective way to talk about personality.
Your Rising sign changes roughly every two hours, so an accurate birth time is the key to an accurate Big Three. Astrology is offered here for reflection and entertainment.
Worked walkthrough: why birth time matters
Take someone born on 15 August 1990 at 2:15 pm in London. The Sun is at about 22.5° Leo, the Moon at about 17.5° Gemini and the Rising sign is Scorpio at about 20.7°. If the same person had been born at 6:00 pm that day, the Sun would be unchanged and the Moon would only have moved a couple of degrees, but the Rising sign would be Capricorn. That is because the Rising sign changes roughly every two hours as the Earth turns. The calculator flags any placement close to a sign boundary so you know when to double-check the birth time.
Getting a reliable result
- Use the time on a birth certificate or hospital record if you can. Family memory is often off by an hour or more, which can change the Rising sign.
- Choose the birth city from the list so the correct time zone, including daylight saving at that date, is used.
- The Sun sign is the most forgiving: it only changes once a month, so small time errors rarely matter for it.
- Western astrology uses the tropical zodiac. Vedic astrology uses a different system and will often give different signs.
- Treat the descriptions as prompts for reflection rather than predictions. Astrology here is offered for entertainment.
What the Big Three are
In Western astrology the Sun, Moon and Rising signs are read together as a short portrait. The Sun sign is usually described as core identity and drive, the Moon sign as emotional style and what feels safe, and the Rising sign (also called the ascendant) as the first impression you give and how you approach new situations.
This is an interpretive tradition, not a scientific measure of personality. The calculator gives you the astronomical positions and descriptions to reflect on, and it is offered for entertainment.
How each placement is worked out
Each sign is 30° of the sky, but the three bodies cross a sign at very different speeds, which is why they need different amounts of information. The positions are found with standard astronomical formulas of the kind collected in Jean Meeus's Astronomical Algorithms, not a simplified lookup table.
| Placement | Time in one sign | What it depends on |
|---|---|---|
| Sun | About 30 days | Birth date; time barely matters |
| Moon | About 2.5 days | Birth date and time |
| Rising | About 2 hours on average | Birth time and birth place |
Why birth place and time zone change the answer
The Rising sign is the sign on the eastern horizon at the moment of birth, so it depends on where you were. Longitude, together with the exact time, sets the local sidereal time, and latitude changes how quickly each sign rises: near the poles some signs sweep across the horizon much faster than others.
Birth times are recorded as local clock time, so the time zone and daylight saving in force on that date must be applied before converting to universal time. Choosing the birth city from the list lets the calculator do this for you.
Signs on the cusp
If a planet sits within about a degree of a sign boundary, a small error in birth time can move it into the neighbouring sign. The Sun changes sign around the 20th–23rd of each month, and the Moon can change sign within a single day. The calculator flags close calls so you know when to double-check the birth time on an official record.
Tropical and sidereal zodiacs
This calculator uses the tropical zodiac of Western astrology, which fixes the start of Aries at the March equinox. Vedic astrology uses the sidereal zodiac, which is offset by roughly 24° today, so many people get a different sign in each system. Neither is wrong, but they answer different questions, so compare like with like.
Element and modality
Every sign belongs to one of four elements (fire, earth, air, water) and one of three modalities (cardinal, fixed, mutable). The result shows both for each placement, which makes it easier to compare combinations, for example two fire signs with a water Moon. The age calculator uses the same birth date if you also want your exact age or the days until your next birthday.
Frequently Asked Questions (FAQs)
Enter your birth date, exact birth time and birth city, then press Calculate. You will see your Sun, Moon and Rising signs together with their degrees.
Your Rising sign depends on the exact time and location, and the Moon changes sign about every two and a half days. Without accurate details, those two placements can be wrong.
Your Sun sign will normally still be right, but the Moon and Rising signs may not be. Check a birth certificate or ask a family member.
It uses standard astronomical formulas that are accurate to a fraction of a degree, but placements within about a degree of a sign boundary should be double-checked with a full ephemeris.
The tropical zodiac used in Western astrology. Vedic (sidereal) astrology uses a different reference and will often give a different sign.
The rising sign changes roughly every two hours as the Earth turns, so a few hours' difference in birth time can give a different rising sign. Sun and Moon signs are far less sensitive, which is why an exact birth time is only essential for the Rising sign.
Your rising sign, or ascendant, is read as your outward style and first impression – how you come across before people get to know you, as distinct from your Sun sign's core identity.
Yes, though it is less common since the Moon moves through all 12 signs roughly every month while the Sun takes a year. Checking both together is what gives the fuller "Big Three" picture.
They are your Sun sign (core identity), Moon sign (emotions and instincts) and rising sign (outward style). Together they give a fuller picture than the Sun sign alone.
Yes, very easily. The rising sign changes roughly every two hours, so two people born hours apart, or in different cities on the same day, can have entirely different rising signs.
For entertainment and reflection. Sun, Moon and Rising placements are calculated with standard astronomical formulas and are approximate, especially near sign boundaries. Astrological descriptions are offered for reflection and entertainment, not as predictions or advice. See our full disclaimer.