Enter a birth date, an exact time and a city, and this free birth chart calculator works out where all ten bodies stood at that moment, divides the sky into twelve houses, and measures every major aspect between them.
It runs in both zodiacs - Western tropical and Vedic sidereal - and offers five house systems, so you can see for yourself exactly why two astrology chart generators sometimes disagree.
The chart shown is a worked example. Replace the details with your own and press Calculate.
The Sun in Cancer protects what it loves and forgets nothing. The Moon in Sagittarius recovers by moving, travelling or planning something distant. With Libra on the ascendant, the chart meets people with charm and an instinct for the agreeable thing to say. That solar emphasis lands in the ninth house, so it plays out through belief and distance. The Moon occupies the second house, tying private need to money and values.
4 of the ten bodies sit in water signs, which tilts the temperament of the whole chart that way. The cardinal signs hold 7 placements, which sets the pace at which this chart tends to move.
The closest major aspect is Mercury trine Pluto, exact to within 0°05′, and still closing. Saturn, Uranus, Neptune and Pluto stood retrograde at this moment, so those functions turn inward before they turn outward.
| Body | Position | House | Motion |
|---|---|---|---|
| Sun | 12°31′ Cancer | 9 | Direct |
| Moon | 5°54′ Sagittarius | 2 | Direct |
| Mercury | 15°00′ Cancer | 9 | Direct |
| Venus | 11°35′ Gemini | 8 | Direct |
| Mars | 24°38′ Aries | 6 | Direct |
| Jupiter | 20°09′ Cancer | 9 | Direct |
| Saturn | 22°45′ Capricorn | 3 | Retrograde |
| Uranus | 7°23′ Capricorn | 3 | Retrograde |
| Neptune | 13°13′ Capricorn | 3 | Retrograde |
| Pluto | 15°06′ Scorpio | 1 | Retrograde |
| House | Cusp |
|---|---|
| First house | 28°27′ Libra |
| Second house | 26°33′ Scorpio |
| Third house | 28°48′ Sagittarius |
| Fourth house | 3°41′ Aquarius |
| Fifth house | 6°53′ Pisces |
| Sixth house | 5°14′ Aries |
| Seventh house | 28°27′ Aries |
| Eighth house | 26°33′ Taurus |
| Ninth house | 28°48′ Gemini |
| Tenth house | 3°41′ Leo |
| Eleventh house | 6°53′ Virgo |
| Twelfth house | 5°14′ Libra |
| Pair | Aspect | Orb | Phase |
|---|---|---|---|
| Mercury – Pluto | Trine | 0°05′ | Applying |
| Sun – Neptune | Opposition | 0°41′ | Applying |
| Mercury – Neptune | Opposition | 1°48′ | Separating |
| Neptune – Pluto | Sextile | 1°53′ | Separating |
| Mars – Saturn | Square | 1°53′ | Separating |
| Sun – Mercury | Conjunction | 2°29′ | Separating |
| Sun – Pluto | Trine | 2°35′ | Applying |
| Jupiter – Saturn | Opposition | 2°36′ | Applying |
| Mars – Jupiter | Square | 4°30′ | Separating |
| Jupiter – Pluto | Trine | 5°03′ | Separating |
| Sun – Uranus | Opposition | 5°08′ | Separating |
| Mercury – Jupiter | Conjunction | 5°09′ | Applying |
| Moon – Venus | Opposition | 5°41′ | Applying |
| Uranus – Neptune | Conjunction | 5°49′ | Separating |
| Jupiter – Neptune | Opposition | 6°56′ | Separating |
| Mercury – Uranus | Opposition | 7°37′ | Separating |
| Sun – Jupiter | Conjunction | 7°38′ | Applying |
| Mercury – Saturn | Opposition | 7°45′ | Applying |
| ☉ | ☽ | ☿ | ♀ | ♂ | ♃ | ♄ | ♅ | ♆ | ♇ |
|---|---|---|---|---|---|---|---|---|---|
| ☉ | |||||||||
| ☽ | No aspect | ||||||||
| ☿ | ☌ | No aspect | |||||||
| ♀ | No aspect | ☍ | No aspect | ||||||
| ♂ | No aspect | No aspect | No aspect | No aspect | |||||
| ♃ | ☌ | No aspect | ☌ | No aspect | □ | ||||
| ♄ | No aspect | No aspect | ☍ | No aspect | □ | ☍ | |||
| ♅ | ☍ | No aspect | ☍ | No aspect | No aspect | No aspect | No aspect | ||
| ♆ | ☍ | No aspect | ☍ | No aspect | No aspect | ☍ | No aspect | ☌ | |
| ♇ | △ | No aspect | △ | No aspect | No aspect | △ | No aspect | No aspect | ⚹ |
Nothing is charged, nothing is gated, and the worked example below is already calculated: change the details and the whole zodiac chart recalculates in place.
A birth chart is a map of the sky drawn from one specific place at one specific minute: the moment and location of a birth. It records where the Sun, the Moon and the eight planets stood against the band of the zodiac, and which part of that sky was rising over the eastern horizon at the time.
Natal chart is the same document under a more formal name - natal simply means "of birth" - and astrologers use the two words interchangeably. You will also see it called an astrology chart, an astro chart or a star chart, and in each case the object being described is identical: one diagram, one instant, one location.
What makes a zodiac chart specific to a person rather than to a day is the pairing of time and place. Everyone born on the same date shares roughly the same planetary signs. Only people born within a few minutes of each other, in the same city, share the same angles and houses.
Three things: the date of birth, the clock time at the birthplace, and the birthplace itself. The city supplies the latitude and longitude, and it also supplies the time zone, which is what lets the calculator work out whether daylight saving was in force on that date - a correction that has misplaced a great many charts by exactly one hour.
The birth time matters more than people expect, and it matters for one reason: the Earth turns. A full rotation carries the entire zodiac past the horizon every twenty-four hours, so the rising degree advances about one degree every four minutes, and the whole rising sign changes roughly every two hours. The midheaven moves at a comparable rate. Ten minutes of error moves the ascendant a couple of degrees; ninety minutes of error can hand you the wrong rising sign entirely, and with it a completely different house for every planet.
The Moon is the other time-sensitive body. It travels between twelve and fifteen degrees a day, so across a twelve-hour uncertainty it can move most of a sign, and if the birth fell near a sign boundary the Moon sign itself is in doubt.
If you do not know the time, this calculator will still do useful work. Tick the box, and it casts the chart for noon at the birthplace. Every planet from Mercury outward stays in the same sign all day, so those placements are reliable. The Sun is reliable except in the rare case of a birthday that falls on the day the Sun changes sign. What genuinely cannot be produced without a time is the ascendant, the midheaven and the twelve houses, and this tool does not invent them: it shows the signs and leaves the house column empty rather than guessing.
A chart is easier to read once you notice it is three separate layers stacked on one diagram, each answering a different question. The planet names the function that is operating. The sign it stands in describes the manner that function is carried out in. The house it falls in tells you which department of ordinary life the whole business is happening in. Function, manner, department - and you need all three before a placement means anything.
Take one example. Mars is the drive to act; in Libra it acts by consulting, delaying and weighing; in the tenth house it does that in public, at work, where other people are watching. Swap any one of the three layers and the picture changes completely.
The ten bodies, and the question each one answers:
Every planet can occupy any of twelve signs and any of twelve houses, and reproducing all of those combinations here would be padding rather than coverage. They are set out properly in each planet through all twelve signs and in planet-by-house interpretations.
Of everything in a chart, three placements do most of the work, and they are the three people mean by the big three: Sun, Moon and rising sign. They are worth separating because they are usually different from one another, which is why "what is your sign" so often produces a description that only half fits.
The Sun sign is what a horoscope column means by your sign, and it depends only on the date. The Moon sign is your private weather - what you need in order to feel settled - and it depends on the date and, near a sign change, the time. The rising sign, or ascendant, is the degree of the zodiac that was climbing over the eastern horizon at the birthplace: it governs first impressions, and it is the placement that sets where all twelve houses begin.
Sun and Moon can be found from a date alone. The ascendant cannot: it needs the time and the place, which is the whole reason this calculator asks for them.
If one of the three is the only thing you came for, there is a dedicated rising sign calculator and a moon sign calculator that answer just that question.
The houses divide the sky as seen from the birthplace into twelve sectors, beginning at the ascendant and running counter-clockwise. Where the signs describe manner, the houses describe subject matter - the actual areas of life a planet is going to show up in.
A house only starts to mean something once a planet occupies it, which is covered one placement at a time in what each planet does in each house.
Planets do not act in isolation. When the angle between two of them lands close to one of a handful of significant values, astrologers call that an aspect, and treat the two functions as wired together. Exactness matters: the closer the angle to the ideal, the louder the connection, and the permitted margin either side is called the orb.
Five major aspects account for most of what is read in practice. This calculator allows eight degrees of orb for a conjunction or opposition, seven for a square or trine and five for a sextile, widened by a degree for each of the Sun and Moon involved.
Minor aspects, competing orb conventions and pair-by-pair meanings are collected in the full aspects reference.
Dividing the sky into twelve is not a settled problem, and astrologers have proposed dozens of ways to do it. The disagreement is about the intermediate cusps, and it exists because the ecliptic is tilted relative to the horizon, so the twelve sectors are only equal at the equator.
Placidus, the modern default, divides each degree’s own day arc and night arc into three equal parts of time, which means its houses are unequal and grow badly distorted at high latitudes. Whole Sign is the oldest approach and the simplest: the rising sign becomes the entire first house, the next sign the second, and so on, so every house is exactly one sign. Koch works from the birthplace horizon, tracking the degrees that were rising at intervals during the midheaven degree’s own climb, and its cusps typically sit a degree or two away from the Placidus ones. Equal houses simply count thirty degrees at a time from the ascendant. Porphyry takes the arc between each pair of angles and cuts it in three.
Now the part that resolves most of the confusion. Switching system changes the house cusps, and it can therefore move a planet that sits near a cusp from one house to the next. It does not change any planet’s position, and it does not change the ascendant: the rising degree is identical in all five systems. So if another calculator gives you the same planets but a different house for one of them, that is a house system difference. If it gives you a different rising sign altogether, the cause is something else - usually a birth time entered wrongly, a daylight saving correction that was missed, a different city, or a sidereal chart being compared against a tropical one.
You can test the claim directly in the calculator above: change the house system and watch the cusp table move while the planet degrees stay put.
Both traditions use the same twelve sign names and the same planets. They disagree about where the zodiac starts.
The tropical zodiac, used across Western astrology, begins at the March equinox and defines zero degrees of Aries as the point where the Sun crosses the celestial equator going north. It is tied to the seasons, not to the stars. The sidereal zodiac, used in Vedic astrology, begins from a fixed point among the constellations instead.
These two starting points used to coincide, and no longer do, because the Earth’s axis wobbles over a cycle of about twenty-six thousand years. That drift, called the precession of the equinoxes, has opened a gap of a little over twenty-four degrees at present, and it widens by roughly fifty arcseconds a year. The gap has a name - the ayanamsa - and this calculator uses the Lahiri value, which is the Indian government standard.
The practical consequence is that a sidereal chart usually puts the Sun in the previous sign, unless the tropical position was already past about twenty-four degrees. Someone who is a tropical Leo at five degrees is a sidereal Cancer. Neither is a mistake; they are two different measuring conventions, and the switch above lets you read the same birth data under each.
The sidereal switch above covers the zodiac itself. For nakshatras, dasha periods and the rest of the Indian apparatus, use the Vedic sidereal birth chart calculator.
Positions are computed from published algorithms rather than looked up in a table. The Moon comes from the abbreviated ELP-2000/82 lunar series as tabulated by Jean Meeus in Astronomical Algorithms. The Sun and the seven planets from Mercury to Neptune come from the VSOP87D series, truncated to the terms that matter over the years this calculator covers and checked against the full series before shipping. Pluto is the exception, and has no VSOP87 series of its own: it uses the Keplerian elements published by the Jet Propulsion Laboratory, which makes it the least precise of the ten. Every position is then corrected for the Earth’s displacement from the Earth-Moon barycentre, for light travel time, for annual aberration, and for nutation, because astrological longitude is measured from the equinox of the birth moment rather than from a fixed frame.
Time handling matters as much as the astronomy. Local clock time is converted using the birthplace time zone and the historical daylight saving rules for that year, and the difference between Universal Time and Terrestrial Time is applied before any position is computed.
The results have been checked two ways. Against documented events: the Moon reproduces the worked example in Meeus to five decimal places, the Sun reproduces his solar example to a fraction of an arcsecond, and the planets are held against the Jupiter-Saturn conjunctions of 2000 and 2020, the Venus transit of 2012, the Mercury transit of 2019, four equinoxes and solstices, and several outer-planet sign ingresses. And against independent implementations of different theories: the full VSOP87 series for the planets, the full ELP/MPP02 lunar theory for the Moon, and Meeus chapter 37 for Pluto. On the worked example above, every one of the ten agrees with those references to within five arcseconds. Across the whole supported range the largest disagreement found is about one arcminute, on Pluto. That is far finer than any interpretive distinction, and finer than the uncertainty in a birth time recorded to the nearest minute.
Three honest limits. The series are fitted for the years 1800 to 2050, and this calculator does not accept dates outside that window. Pluto is verified against an independent theory only from 1885 onward, which is as far back as that theory itself reaches, so for births before then its degree carries more uncertainty than the other nine. And Placidus and Koch houses genuinely cease to exist inside the polar circles, where some degrees never rise; there the calculator substitutes Porphyry and tells you it has done so, rather than printing a number that means nothing.
The formulas, the reference sources and the measured error bounds are written up in the methodology note.
One consequence of doing the arithmetic in your browser deserves stating plainly: your birth details never leave your device. There is no request to a server, no account, and no database row, so there is nothing held anywhere to be lost or sold, and closing the tab is enough to discard it.
There is no difference. Both name the same thing: a map of the sky as it stood at one moment, from one place - the moment and place of a birth. Natal simply means "of birth", so a natal chart is a birth chart in more formal language. Astrology chart, astro chart, star chart and zodiac chart all refer to the same diagram.
The date of birth, the clock time at the birthplace, and the birthplace. The city gives the calculator the latitude and longitude it needs, and it also identifies the time zone, which determines whether daylight saving applied on that date.
Because the Earth turns. The whole zodiac passes the horizon once a day, so the rising degree advances about one degree every four minutes. Ten minutes of error shifts the ascendant a couple of degrees; over an hour or two of error can change the rising sign completely, which moves every house and therefore relocates every planet in the chart.
Yes, with a clear limit. Tick the unknown time box and the chart is cast for noon at the birthplace. Everything from Mercury outward keeps the same sign all day, so those placements are safe, and the Sun is safe except on the day it changes sign. What is missing is the ascendant, the midheaven and all twelve houses, which cannot be determined without a time. This calculator leaves the house column empty rather than guessing.
Different houses usually mean a different house system. Placidus, Koch, Equal, Porphyry and Whole Sign each divide the sky differently, so a planet near a cusp can land in either of two houses while its zodiacal degree is unchanged. A different rising sign is another matter: the ascendant is identical in all five systems. That points to the input: a wrong birth time, a missed daylight saving correction, the wrong city, or a sidereal chart compared with a tropical one.
Placidus is the modern Western default and a reasonable start. Whole Sign is the oldest method and the standard across Indian astrology; it gives one sign per house, which many find easier to read, and it stays well behaved at high latitudes where Placidus distorts badly. Koch usually lands within a degree or two of Placidus. No arithmetic test settles which is correct, so pick one and switch systems above to see how much it changes your own chart.
Where the zodiac starts. Tropical astrology begins at the March equinox, tying the signs to the seasons; Vedic astrology begins from a fixed point among the stars. The two once coincided, but the Earth’s axis wobbles over roughly twenty-six thousand years, and that precession has opened a gap of just over twenty-four degrees, growing about fifty arcseconds a year. The gap is the ayanamsa; this calculator uses the Lahiri value. A sidereal chart usually moves the Sun back one sign.
They carry most of the interpretive weight, and they are usually three different signs. The Sun is the one a horoscope column means, and it comes from the date. The Moon describes what you need in order to feel settled, and it comes from the date plus, near a boundary, the time. The rising sign is the degree climbing over the eastern horizon at your birthplace; it shapes first impressions and sets where all twelve houses begin.
Roughly every two hours. The full circle of the zodiac passes the horizon in about twenty-four hours, which works out at one sign per two hours and one degree per four minutes. That rate is exactly why an approximate birth time is not good enough for house placements, and why a birth certificate time beats a family recollection.
About every two and a half days. The Moon covers twelve to fifteen degrees of the zodiac daily, which is a whole sign in roughly sixty hours. For most birthdays that means the Moon sign is unambiguous even without a time, but for a birth that happens to fall near a boundary the time is what decides it.
Aspects are significant angles between two planets. A conjunction is zero degrees apart, a sextile sixty, a square ninety, a trine a hundred and twenty and an opposition a hundred and eighty. The tolerance either side is the orb, and this calculator uses eight degrees for conjunctions and oppositions, seven for squares and trines and five for sextiles. The aspect table above lists them from the tightest outward and marks whether each is still closing or already separating.
To within about an arcminute at worst, and five arcseconds on the example chart above. The Moon comes from the ELP-2000/82 series, the Sun and the planets out to Neptune from VSOP87D, and Pluto from Keplerian elements. All are corrected for light travel time, aberration, the Earth’s offset from the Earth-Moon barycentre and nutation, then checked against independent implementations of the full theories. Dates run from 1800 to 2050. The full working is set out in the methodology note.
Yes, because it never leaves your device. The whole calculation runs in your browser: no birth date, time or place is transmitted to a server, stored in an account or written to a database, and there is nothing to delete afterwards. Closing the tab discards it. The formal statement is in the privacy policy.
This page is the general-purpose calculator. These cover the neighbouring questions in more depth.