Free astronomical tools
Astrology calculators that show their work.
Find a placement, lunar phase, or planetary cycle with Swiss Ephemeris calculations, plain-language results, and honest notes about what your birth details can support.
- Swiss Ephemeris
- No birth data stored
- No account required
- Method explained
Choose your question
Twelve focused ways into one complete sky
Use a focused calculator for a quick answer, or begin with the complete birth chart when you want placements, houses, and aspects together.
Free calculator
Birth Chart Calculator
Your complete natal wheel with planets, houses, aspects, exact degrees, and clear accuracy notes.
Date and place; time for houses and Rising signFree calculator
Sun, Moon & Rising / Big Six Calculator
Calculate Sun, Moon, Rising, Mercury, Venus, and Mars from the exact birth moment.
Date, time, and birthplaceFree calculator
Zodiac Compatibility Calculator
Compare two signs for a quick read or two birth dates across Sun, Mercury, Venus, and Mars.
Two signs or two birth datesFree calculator
Moon Sign Calculator
Find your Moon sign, exact degree, motion, sign-change window, and a visible warning when the birth time is needed to confirm the result.
Birth date; time and place improve boundary accuracyFree calculator
Moon Phase Soulmate Calculator
Calculate your birth Moon phase and complementary phase, then optionally compare two birthdays to see how their lunar silhouettes fit.
Birth date; time and place improve boundary accuracyFree calculator
Venus Sign Calculator
Find your Venus sign, exact degree, retrograde status, and house when an accurate birth time is supplied.
Birth date; time and place improve boundary accuracyFree calculator
Rising Sign Calculator
Calculate your Rising sign and exact Ascendant degree from your recorded birth time and birthplace.
Date, exact time, and birthplaceFree calculator
Mars Sign Calculator
Calculate your Mars sign, exact degree, retrograde status, and the dated sign window containing your birth.
Birth date; time and place improve boundary accuracyFree calculator
North Node Calculator
Calculate your True North Node, opposite South Node, exact degrees, houses, and future nodal-return peaks.
Birth date; time and place improve boundary accuracyFree calculator
Jupiter Sign Calculator
Find your Jupiter sign, exact degree, retrograde status, and the sign window containing your birthday.
Birth date onlyFree calculator
Neptune Sign Calculator
Calculate your Neptune sign, degree, retrograde status, and the exact peaks of major Neptune cycle aspects.
Birth date onlyFree calculator
Saturn Return Calculator
Calculate your natal Saturn degree and the exact conjunction peaks of your first, second, and third Saturn returns.
Birth date onlyAccuracy before certainty
The right input depends on what is being calculated.
Slow planets can usually be located from a date alone. The Moon benefits from a time near a sign or phase boundary. A Rising sign cannot be calculated responsibly without an exact time and place because the horizon changes throughout the day.
Each Zodiaro tool asks only for the data it needs and explains when a result is approximate. Astrology is offered for reflection and education, not as proof, prediction, or professional advice.