How to Read a Birth Chart, Step by Step

To read a birth chart, work from the general to the particular: start with your Sun, Moon and rising signs, then look at each planet, the sign it is in, the house it falls in, and finally the aspects, the angles that link the planets. A common way astrologers teach this is a three-part shortcut: the planet is what, the sign is how, and the house is where. This guide turns that into eight steps, from getting an accurate chart to pulling the pieces together, and follows an invented example chart all the way through so you can see each step used. Astrology is a tradition, and everything below is offered for reflection and entertainment.

What a birth chart is

A birth chart, also called a natal chart, is a map of the sky for one moment and one place: where the Sun, Moon and planets stood among the twelve zodiac signs, and how the sky was divided into twelve houses, when you were born. The positions are astronomy and can be checked against an ephemeris. The meanings are the tradition, and the reading is the art of combining them.

Four ingredients make up every chart: planets, signs, houses and the aspects that link the planets. The steps below take them one at a time.

Step 1: Get an accurate chart

Everything depends on three details: your birth date, your birth place and your birth time. Use the time on your birth certificate if it has one, in local time, and the town where you were born.

The place matters because the sky looks different from different latitudes. We computed how long each sign spends rising over the eastern horizon for one date (21 June 2001): at the equator every sign takes between 1.85 and 2.14 hours, while at 51.5 degrees north Aries takes 0.88 hours and Virgo 2.84. So an error of an hour in the birth time is more likely to change the rising sign at 51.5 north, where Aries passes in under an hour, than at the equator.

What an unknown birth time removes

Without a time, a chart is still useful, but three things are lost: the Ascendant (the rising sign), the Midheaven and the houses. The Moon moves about 13 degrees a day and spends roughly 2.3 days in each sign (across 21,915 days from 1950 to 2009 we counted it at 8.28% to 8.37% of days in each sign), so on some dates it changes sign during the day itself, and without a time you cannot tell which sign you were born under. Our methodology page explains what we do on the days when the Moon changes sign.

Choose a house system and note it down

Two charts of the same person can look different if they use different house systems, so write down which one yours uses. Our calculator defaults to Placidus and can switch to Whole Sign, and it shows the system it used in the result. If you are comparing your chart with one from another site, check this setting first, because it is one reason two charts can disagree about a house.

Step 2: Start with the big three

Most astrologers begin with three placements: the Sun sign, the Moon sign and the rising sign. Many guides describe the Sun as core identity, the Moon as the emotional world and the rising sign as the way you present yourself. Older texts say something similar in their own words. Alan Leo (1899) wrote that “The Sun represents the heart, the higher emotions, the purer part of our nature” and that “the Moon represents the brain, the senses”. Sepharial (1910) explained that a person is said to be under a sign when it is “rising in the East at the moment of birth”.

Our example chart, for an invented person born on 15 June 1990 at 2:30 pm in Chicago, has the Sun at 24 degrees 26 minutes of Gemini, the Moon at 19 degrees 33 minutes of Pisces and the Ascendant at 14 degrees 39 minutes of Libra. Read as tradition, that is a Gemini Sun, a Pisces Moon and Libra rising. Each placement is a starting point, and the Sun, Moon and rising guide goes into how to read all three.

Reading the three together

Do not read the big three as separate boxes. Try one sentence that holds all of them, such as “a curious Sun, a receptive Moon and a courteous first impression”, and notice where the words pull against each other. Astrologers often find that the friction between placements is where a chart gets interesting. In the example chart the Sun and Moon are 90 degrees apart, which we come back to in Step 6.

Step 3: Read the planets

The Sun and Moon are called luminaries, and the eight planets are the other bodies in the chart. Each is traditionally linked with a function, and Sepharial (1910) gives short descriptions that show how early twentieth-century astrologers saw them. Here we keep to short phrases and leave out the sections that are about fortune or health.

The Sun to Mars

For the Sun, Sepharial (1910) lists being “magnanimous, noble, proud”. For the Moon he gives “gracefulness of manner and suavity of speech”. For Mercury he writes “active, versatile, apt and business-like”, and for Venus “good taste, fine feeling, artistic powers”. For Mars he lists “much ambition and executive ability”. In our own summary of the modern reading, the Sun stands for identity and purpose, the Moon for needs and feelings, Mercury for thinking and communication, Venus for affection and values, and Mars for drive and action.

Jupiter and Saturn

Sepharial (1910) gives Jupiter “joviality, optimism, bountifulness, generosity” and Saturn “steadfastness, patience, and endurance”. In our own summary, Jupiter stands for growth and meaning and Saturn for structure and responsibility. As astronomy, Saturn takes about 29.4 years to go round the zodiac (NASA gives 29.424 tropical years) and stays in a sign for about two and a half years on average. Our Saturn return calculator shows the exact dates for your chart.

Uranus, Neptune and Pluto

Sepharial (1910) associates Uranus with “originality, inventiveness”. Neptune, found by telescope in 1846, is slower still, at roughly 164 years to go once round the Sun (NASA gives 59,800 days). Modern astrology associates it with idealism, dreams, artistry and empathy, and also with illusion and vagueness, as Wikipedia’s summary of the planets in astrology lists them. Wikipedia’s summary of modern astrology calls Pluto “the great renewer”, the part of a person that “destroys in order to renew”. These three planets change sign so slowly that they say more about a stretch of years than about one person, so many astrologers read them mainly through the house they fall in and the aspects they make.

Step 4: Add the signs

The sign tells you how a planet is dressed, in the language of astrology. Signs come in groups. Sepharial (1910) sorts them by element: fire for Aries, Leo and Sagittarius, earth for Taurus, Virgo and Capricorn, air for Gemini, Libra and Aquarius, and water for Cancer, Scorpio and Pisces. He also sorts them by mode, using the names movable, fixed and flexed, which astrologers now usually call cardinal, fixed and mutable. Movable signs are Aries, Cancer, Libra and Capricorn, fixed are Taurus, Leo, Scorpio and Aquarius, and flexed are Gemini, Virgo, Sagittarius and Pisces.

Counting the balance

A quick way to read a chart is to count how its planets spread across the elements and modes. Our chart tool does this with a weighting: the Sun, the Moon and the Ascendant count twice, Mercury through Saturn once. In the example chart that gives air 5, water 3, earth 2 and fire 1, and cardinal 5, mutable 5 and fixed 1. An astrologer would notice that air is the strongest element, that fire is thin and that the fixed mode is nearly absent. That is a description of emphasis, a prompt for reflection rather than a verdict.

The tropical zodiac

Most Western astrologers use the tropical zodiac, in which 0 degrees of Aries is the March equinox, so the signs follow the seasons rather than the star constellations. Our calculators use it too. Hindu astrology uses the sidereal zodiac and gets different signs for many people.

Step 5: Add the houses

The houses turn the chart into areas of life. Popular guides describe them as segments that represent distinct areas of your life, from identity and resources to home, work, partnership and community. Their edges depend on the system used. Placidus, the default in our calculator, is described by Wikipedia as the most commonly used system in modern Western astrology, and it is not the only option. Wikipedia notes that “each one represents a different compromise”. Our guide to the 12 houses in astrology covers each one and both main systems.

In the example chart under Placidus, the Sun and Jupiter are in the 9th house, the Moon is in the 5th, Mercury and Venus are in the 8th, Mars is in the 6th, Saturn and the Moon’s North Node are in the 4th, Uranus and Neptune are in the 3rd and Pluto is in the 2nd. Five houses hold no planets: the 1st, 7th, 10th, 11th and 12th. Six of the ten planets sit in houses 1 to 6, the half of the chart below the horizon, and four sit above it, in the 8th and 9th. Empty houses are normal in every chart.

Angular houses carry extra weight

The 1st, 4th, 7th and 10th are the angular houses, the ones that begin at the four angles of the chart. Traditionally, astrologers treat planets in them as the most prominent in a chart, and planets right on an angle as more prominent still. In the example chart Saturn is in the 4th house under Placidus, and Jupiter sits just before the Midheaven, which we come back to in Step 7.

Reading one house at a time

A simple routine works for any house. Note the sign on its edge, note any planets inside it, and then find where the planet that traditionally rules the edge sign sits, since astrologers read the two houses together. In the example chart the 5th house edge is in Aquarius, and the Moon is inside the house, so a reader would describe the 5th house through both its edge sign and its occupant. Practice on the house you are most curious about before trying all twelve.

Step 6: Look at the aspects

Aspects are the angles between planets, measured around the circle. Sepharial (1910) lists the “sextile of 60 degrees, square of 90 degrees, trine of 120 degrees”; the two others are the conjunction, where planets sit together at 0 degrees, and the opposition, at 180. Astrologers allow a few degrees of leeway, called an orb. We use 8 degrees for conjunctions and oppositions, 7 for squares and trines and 5 for sextiles, with 2 extra degrees when the Sun or Moon is involved. The smaller the orb, the tighter the aspect.

Many guides sort the aspects into easy and hard. Wikipedia writes that “aspects are considered to be either easy” (the sextile and trine) “or hard” (the square and opposition). Almanac.com puts it as “Favorable aspects indicate an easy flow of energy”, and Saturn and Honey calls trines “soft, harmonious aspects”. The conjunction can go either way depending on the planets involved. This is a convention of interpretation, and it has no measurement behind it.

How many to read

A chart can list dozens of aspects. Our example chart has 29, of which three are within 1 degree and eight within 2. A sensible habit is to start with the tightest, and to keep an eye out for the aspects that involve the Sun, the Moon and the Ascendant, since they touch the placements you have already read.

Step 7: Pull it together with the example chart

Reading a chart is combining the layers into a few themes. Here is how an astrologer might read three features of our invented example chart. These are observations about the tradition, not statements about anyone.

The Moon and Venus in a close aspect

The Moon at 19 degrees 33 minutes of Pisces and Venus at 19 degrees 9 minutes of Taurus are 60 degrees apart, a sextile with an orb of 0.41 degrees, the tightest aspect in the chart. Tradition links the Moon with feelings and needs and Venus with affection and values, and describes a sextile as an easy pairing, so an astrologer would say the two placements are described as working together.

A cluster in Capricorn

Saturn, Uranus and Neptune all sit in Capricorn, and Uranus and Neptune are within 5.56 degrees of each other. Since they are slow planets, an astrologer would read them through their houses. Under Placidus that puts two of them in the 3rd house and Saturn in the 4th, which links the themes of communication and home.

Jupiter at the top of the chart

Jupiter is at 15 degrees 57 minutes of Cancer, within 1.29 degrees of the Midheaven at 17 degrees 15 minutes of Cancer, an aspect that astrologers call a conjunction. The Midheaven is the highest point of the chart and popular guides associate it with career and public image. Jupiter also squares the Ascendant, with an orb of 1.31 degrees. An astrologer would call Jupiter prominent in this chart, since it touches two of its main points.

Put together, the chart carries an emphasis on air, a close Moon and Venus aspect, and a prominent Jupiter. Each of these can be explored further, and none of them tells anyone what to do.

Three questions to ask of any chart

When you look at your own chart, three questions keep the reading organized. Which placements repeat a theme, for example several planets in the same element or the same house? Which aspects are tightest, since a small orb is read as a stronger link? And which points, the Sun, Moon or Ascendant, are touched by other planets? Write down the answers in plain words before you reach for a long description, because a short list of your own observations is easier to come back to than a long one copied from a book.

Step 8: Know what a chart cannot do

A birth chart does not predict your life and it cannot tell you what to do. Wikipedia’s entry on astrology says studies “have shown it to have no scientific validity or explanatory power”. We say so plainly because we think you should read a chart the way you would read a poem or a personality quiz: as a source of questions, a language for reflection and a bit of entertainment. It is not a substitute for advice from a professional on health, money, law or relationships.

Habits that keep a reading useful

Three habits help. Read placements as “astrologers traditionally associate”, never as “this is what will happen”. Check the house system and the zodiac before you compare your chart with someone else’s, because a chart drawn in Whole Sign houses or in the sidereal zodiac will not match one drawn in Placidus and the tropical zodiac. And when two traditions disagree, which they often do, keep both in view instead of blending them into one confident answer.

If you enjoy the tradition, the natural next step is your own chart. The calculator gives you every placement in this guide for free, and a synastry chart sets two charts side by side if you want to compare yours with someone else’s. If you would like all of it written up in one place, there is a personal reading.