Calculators
Free astrology calculators
Eight calculators from the same VSOP87 sky. Natal draws the full wheel — Sun, Moon, rising, houses, aspects — and reads from a written cache, not a model inventing degrees. Separate pages isolate rising, Moon, Mercury, Venus and Mars; synastry overlays two charts; composite is the shorter-arc midpoint.
All eight calculators
Natal is the full instrument. Rising needs a clock time. Moon, Mercury, Venus and Mars isolate one body. Synastry overlays two charts; composite is a relationship midpoint, not a Davison chart. All are free without an account; synastry and composite allow one overlay before a sign-in.
Natal chart
Birth chart calculator
Planetary positions computed from a VSOP87 / lunar ephemeris for your exact date, time and coordinates. Tropical zodiac, Placidus houses.
Rising
Rising sign calculator
The Ascendant is the ecliptic degree rising on the eastern horizon at birth. It needs a clock time — a twenty minute error can move it five degrees.
Sun
Sun sign calculator
The Sun spends about a month in each sign, so the date is usually enough. Born within a day of a boundary? This works it out from the real position rather than a table of dates, which is where the year matters.
Moon
Moon sign calculator
The Moon moves about half a degree per hour, so a birth time still matters. Without one, the sign is usually right and the degree is a noon estimate.
Mercury
Mercury sign calculator
Mercury changes sign every few weeks and retrogrades three times a year. A birth date is usually enough for the sign; time places it in a house.
Venus
Venus sign calculator
Venus changes sign every few weeks. A birth date is enough for the sign; time places it in a house.
Mars
Mars sign calculator
Mars spends about six or seven weeks in a sign. A birth date is enough for the sign; time places it in a house.
Synastry
Synastry calculator
Two charts on one wheel. Gold glyphs are person A, muted glyphs are person B. Aspects below are between the two charts, not within one.
Composite
Composite chart calculator
Each planet is the shorter-arc midpoint of the two natal positions. Houses follow the midpoint Ascendant in whole sign. This is a relationship chart, not a Davison (midpoint in time) chart.
Transits
Transit calculator
Your birth chart never moves. The planets do. A transit is the angle between where a planet is right now and where it stood when you were born — and unlike a Sun-sign horoscope, it is read against your own degrees.
Today’s sky
Daily horoscope for twelve signs
Readings from today’s tropical sky at 12:00 UTC. Add a birth date for your actual Sun degree — still not a natal chart.
Open today’s horoscopeHow to use a calculator
Every tool on this site takes the same three inputs. The natal calculator shows the full sky; the others isolate one question.
1. Birth date
Use the civil date on the birth record. The Sun, Mercury, Venus and Mars usually need only this for the sign.
2. Birth time
The Ascendant moves about one degree every four minutes. If the time is unknown, tick the box: planets still calculate, houses do not.
3. Birthplace
Type a city. Coordinates and the IANA timezone on that date convert local clock time to Universal Time.
4. Read the instrument
Wheel first, then Big Three, then the light reading card, then the positions table. Save the chart to keep a full report and a day-by-day sky log.
What is being computed
Tropical zodiac, Placidus houses by default, major aspects at 8° / 6° / 4°. Engine: astronomy-engine (VSOP87 / lunar theory). Not Swiss Ephemeris. Not sidereal, Vedic or Chinese astrology.
Articles
Longer notes on the questions people actually search: natal charts, rising signs, birth time, houses, synastry. Same voice as the rest of the site — second person, no medical or financial advice.
Basics
What is a natal chart?
A natal chart is a map of the sky from your birth date, time and place: planets, Ascendant and twelve houses. It is not a daily Sun-sign horoscope or a quiz.
Read the articleBasics
Natal chart vs horoscope
A natal chart is your birth-sky map from date, time and place. A horoscope is usually a Sun-sign column. They are not the same reading and should not be swapped.
Read the articlePlacements
What is my sun sign?
Your Sun sign is the tropical zodiac sign the Sun occupied on your birth date. You usually do not need a birth time. It is one placement, not the whole natal chart.
Read the articlePlacements
Sun, Moon and rising: the Big Three
The Big Three are Sun, Moon and rising sign. Sun from the date, Moon from date plus a check on time, rising only with birth time and place. Read them together.
Read the articlePlacements
What is my rising sign?
Your rising sign is the zodiac degree on the eastern horizon at birth — the Ascendant. It needs an accurate birth time and place. Without a birth time, skip it.
Read the articlePlacements
What is a Moon sign?
Your Moon sign is the tropical sign the Moon occupied at birth. It changes every two and a half days. Time still matters for the degree, the house and cusp days.
Read the articlePlacements
What is a Venus sign?
Your Venus sign is the tropical sign Venus occupied at birth. It describes style in attraction, taste and values — a natal coordinate, not a dating verdict.
Read the articlePlacements
What is a Mercury sign?
Your Mercury sign is the tropical sign Mercury occupied at birth. Mercury stays near the Sun, so the signs match or neighbour. Time still sets house and degree.
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