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Big Three Calculator

Your Big Three are your Sun, Moon, and rising signs. Calculate them with your birth date, local birth time, and birthplace. Without a birth time, you can still check supported Sun and Moon signs, but rising stays unknown. This free calculator explains any sign uncertainty instead of guessing a complete result.

Your progress stays in this tab when you switch calculators.

Your free Big Three preview

Birth date
How certain is your birth time?
Local birth time
AM or PM

Choose AM for before noon or PM for noon and after.

    Type a city or postal code, then use arrow keys and Enter to select. Include the region if needed.

    No signup. Complete chart and reading: $6.95. One-time purchase. No subscription.

    Three starting points, one birth chart

    In astrology, the Sun is a starting point for purpose, the Moon for comfort and emotional habits, and rising for how you enter an encounter. Reading them together adds context to a single sign. Your free preview connects the supported signs in a short interpretation; the full reading explores the wider chart.

    Explore the guide · See our calculation accuracy evidence

    Questions before you calculate

    What are my Sun, Moon, and rising signs?

    They are the tropical signs containing your Sun, Moon, and Ascendant at birth. Use your birth date, local time, and place in the calculator above. The Ascendant depends on both time and location, so a birthday alone cannot establish all three.

    Is this a free birth chart with Sun, Moon, and rising?

    The supported Big Three signs and short personal preview are free. The full calculated wheel, placement table, houses, aspects, connected reading, and PDF belong to the optional complete reading. No signup is needed for the preview.

    Do I need my exact birth time for a birth chart?

    A known birth time is needed for a specific Ascendant and houses. An approximate time can support a complete chart only if the required output stays consistent across the selected window. Without a time, we provide supported Sun and Moon information.

    Can all three signs be the same?

    Yes. Each point is calculated independently, and several can occupy the same sign. A shared sign does not make the points interchangeable: the Sun, Moon, and Ascendant have different roles in an astrological reading.

    Which zodiac and house system does this use?

    LunarOtter uses the Western tropical zodiac and Whole Sign houses. The Midheaven is calculated separately from the tenth house. The same settings and engine power all three free calculators and the complete reading.