Compatibility calculators

Start with the information you have and the comparison you want. Birth charts use dates, local times and places; known-sign and known-nakshatra views work with those coordinates directly.

Calculator	What you can compare
Zodiac sign compatibility	Compare known Sun signs, conventional date ranges or exact birth Sun positions in romance, friendship and work.
Synastry chart calculator	Compare the planets in two birth charts by exact angular distance, then read the contacts and directional house overlays.
Birth chart calculator	Find the Sun, Moon, planets, Ascendant and house positions for a birth date, time and place.
Sun, Moon and rising calculator	Read the Big Three together: the Sun’s identity theme, the Moon’s emotional needs and the Ascendant’s outward approach.
Composite chart calculator	Combine two natal charts into one chart of planetary midpoints and compare the resulting aspects.
Davison relationship chart calculator	Cast the sky at the midpoint of two birth instants and the geographic midpoint of their birthplaces.
Moon sign compatibility by birth date	Compare the two Moons: their signs, exact separation and traditional emotional themes.
Venus sign compatibility by birth date	Compare each person’s Venus position and the themes of affection, pleasure and values.
Mars sign compatibility calculator	Compare the two Mars positions and their traditional themes of initiative, desire and disagreement.
Mercury sign compatibility calculator	Compare communication themes through each person’s Mercury sign and the exact aspect between them.
Rising sign compatibility calculator	Calculate two Ascendants and compare their exact angle and outward styles.
Sun–Moon compatibility calculator	Compare Person 1’s Sun with Person 2’s Moon, and Person 1’s Moon with Person 2’s Sun.
Venus–Mars compatibility calculator	Compare affection and desire in both directions: Venus to the other person’s Mars, and Mars to their Venus.
Sidereal relationship chart calculator	Compare two charts with a selected sidereal zodiac origin and show the offset used for each birth.
Progressed synastry calculator	Advance both natal charts to an evaluation date, then compare their progressed planetary contacts.
Progressed composite calculator	Progress both natal charts to the chosen date, then calculate the midpoint composite of those progressed positions.
Draconic synastry calculator	Move the chosen north node of each chart to zero Aries, then compare the transformed charts.
Group composite chart calculator	Combine three to twelve charts with an equal-weight circular mean for each planetary position.
First meeting chart calculator	Cast the event chart for the date, time and place of a first meeting, then explore its relationship symbolism.
Relationship transit calculator	Find exact transit contacts to either person’s natal chart or the midpoint composite within your chosen date window.
Synastry declination calculator	Compare planetary declinations for parallels and contraparallels, alongside their north or south positions.
Synastry aspect pattern finder	Find grand trines, T-squares, yods and grand crosses that include planets from both charts.
Chinese zodiac comparison	Find two year animals with a chosen New Year or Li Chun boundary; compare branch relations and stem phases.
BaZi comparison	Compare four natal pillars in both charts, with day-boundary and solar-clock choices.
Chinese and Western signs	Keep each person’s Chinese year animal and Western Sun sign together as separate coordinates.
Kundli / Ashtakoota matching	Calculate eight Moon-based components and their raw total out of 36 with the named Saravali table.
Nakshatra and pada	Find Moon mansion and quarter, retaining all possible categories when a birth time is unknown.
Porutham comparison	Read ten named South Indian rules separately from the eight-component Ashtakoota score.
Navamsa comparison	Compare each sidereal planet’s D9 sign and the D9 Ascendant when birth time is known.
Numerology comparison	Compare name or birth-date numbers with visible Pythagorean/Cheiro reductions and master-number choices.
Birthday Moon phases	Calculate both birth-date Moon phases from the Sun–Moon elongation and compare their phase themes.
Sun sign finder	Resolve a tropical Sun sign from a birth instant or look up a conventional month-and-day range.
Wedding date window	Compare Moon and Venus electional factors at a chosen ceremony clock time and location.

An unknown time keeps the date’s possible planet signs and omits horizon angles. A chart of midpoints and a chart of the midpoint time answer different questions; choose composite or Davison accordingly.