Calendars & dates / Zodiac
Birth Chart Calculator
Make a free tropical natal chart with your big three, a chart wheel, planetary degrees, houses and aspects.
Birth Chart Calculator: Calculates your tropical birth chart with the Sun, Moon, eight other planets and a lunar node. See your big three, a zodiac wheel, planet degrees, retrograde motion, house cusps and the five main aspects. Choose Placidus, Whole Sign or Equal houses. If your birth time is unknown, a noon chart shows the planets and hides houses and rising sign. Astrology is a cultural and entertainment practice; this result makes no predictions. Runs 100% locally in your browser with zero server file uploads.
- Category
- Astrology & fortune
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- In your browser
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- Free · no sign-up
- Availability
- Ready to use
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Traditional planet, sign and house meanings
In astrological tradition, the Moon sign is associated with emotions and comfort. These keywords describe cultural symbolism, not measured personality traits.
- Sun: identity and expression.
- Moon: emotions and comfort.
- Mercury: thought and communication.
- Venus: affection and values.
- Mars: initiative and drive.
- Jupiter: growth and perspective.
- Saturn: boundaries and responsibility.
- Uranus: change and independence.
- Neptune: imagination and ideals.
- Pluto: intensity and transformation.
- Lunar node: symbolic direction and development.
- Aries
- Initiative and directness.
- Taurus
- Steadiness and sensory comfort.
- Gemini
- Curiosity and conversation.
- Cancer
- Care and belonging.
- Leo
- Warmth and expression.
- Virgo
- Practical care and attention.
- Libra
- Harmony and companionship.
- Scorpio
- Depth and emotional privacy.
- Sagittarius
- Freedom and exploration.
- Capricorn
- Structure and responsibility.
- Aquarius
- Independence and community.
- Pisces
- Imagination and sensitivity.
- 1 · Self and presentation.
- 2 · Resources and values.
- 3 · Learning and communication.
- 4 · Home and roots.
- 5 · Creativity and enjoyment.
- 6 · Routines and service.
- 7 · Partnerships.
- 8 · Shared resources and intimacy.
- 9 · Exploration and beliefs.
- 10 · Public life and vocation.
- 11 · Friends and communities.
- 12 · Solitude and reflection.
Astrology is a cultural and entertainment practice; this result makes no predictions.
City data: GeoNames, cities15000, filtered to population 50,000 or more plus capitals; alternate names included. Licensed under CC BY 4.0. GeoNames attribution
How the chart is computed
The chart uses the tropical zodiac: twelve equal 30-degree signs measured from the equinox. Positions are apparent and geocentric, expressed in the true ecliptic and equinox of the birth date. Planet calculations account for light travel time and aberration; the lunar model supplies the Moon's geocentric position. The lunar node is the ascending intersection of the lunar orbit and ecliptic. The mean node follows a standard secular formula; the true node uses the instantaneous lunar orbital plane.
Placidus divides diurnal and nocturnal arcs into thirds. Whole Sign starts the first house at the beginning of the rising sign; Equal starts it at the ascendant's degree. At latitudes of 66 degrees or more, or when Placidus cannot be resolved, Whole Sign is used with a notice. The five aspects are conjunction, sextile, square, trine and opposition. Orbs are 8 degrees when the Sun or Moon is involved, 6 degrees otherwise, and 4 degrees for all sextiles. Each listed orb is the absolute difference from the exact aspect angle.
Sources: Jean Meeus, Astronomical Algorithms, second edition, chapters on sidereal time, coordinates and lunar motion; astronomy-engine documentation (https://github.com/cosinekitty/astronomy) describes the MIT-licensed astronomical calculations. GeoNames city data (https://www.geonames.org/) is licensed under CC BY 4.0; the city search includes places with at least 50,000 residents and capitals.
The big three explained
The Sun sign describes the Sun's position in the tropical zodiac. In astrological tradition it is associated with identity and expression. The Moon sign is associated with emotions and comfort. The rising sign is the ecliptic degree meeting the eastern horizon at the birth instant and place; traditionally it is associated with presentation and approach.
These interpretations belong to a cultural and entertainment practice. The astronomical coordinates can be computed, but the keywords are not scientific measurements of character. They do not predict events or determine compatibility.
How to use it
- Enter your birth date, local time and city, or select time unknown.
- Confirm the time zone and choose a house system and lunar node.
- Calculate your chart, read the big three and save a share card or chart wheel.
Privacy & limitations
Your birth details and chart stay in this browser. Share cards never include your date, time or place.
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Frequently asked questions
Why does the birth time matter?
The ascendant and houses depend on the Earth's rotation and can move noticeably within minutes. The Moon can also change sign during a birth date. Use the recorded local time and the historical time zone when you know them.
Which house system should I choose?
Placidus divides daily arcs and is a common default. Whole Sign gives each zodiac sign one house; Equal starts twelve 30-degree houses at the ascendant. These are different astrological conventions. Placidus falls back to Whole Sign at high latitudes.
How accurate are the positions?
An astronomy library computes the positions at about arcminute level for ordinary modern birth dates. Planet longitudes are checked against independent reference charts from 1950 to 2023. A rounded birth time or an incorrect historical UTC offset can introduce much larger differences, especially for the ascendant.
What are the big three?
The big three are the Sun sign, Moon sign and rising sign. Astrological tradition associates them with expression, emotional comfort and outward presentation. They are cultural interpretations and make no predictions.
What if I do not know my birth time?
The birth chart's time-unknown option uses local noon and hides the ascendant, Midheaven and houses. The Moon calculator checks the whole local date and shows any sign changes with their local times. Two possible Moon signs need a birth time to distinguish them.
Are my birth details private?
All calculations and image exports happen in your browser. Your date, time and place are not uploaded or included on the share card.
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