Synastry: compare two birth charts
Enter two people's birth details to see how the planets in one chart meet the planets in the other. We compare each person's Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn, and the Ascendant when the birth time is known, and list every classical aspect between them, tightest first. There is no overall score: the contacts are the reading.
Beyond Aries and Leo: enter both birth dates to see the whole picture.
How this works
Each chart is computed with our own engine at the given time and place (local noon if the time is unknown). We compare seven planets per person: the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn, and the Ascendant when the birth time is known (it moves through every sign in a day). A contact counts when two of them form one of the five classical aspects (conjunction, sextile, square, trine, opposition) within an orb of 6°, or 4° for the sextile, plus 1° when the Sun or the Moon is involved. Contacts are ranked by orb, tightest first.
Studies of large populations have found no link between astrological pairings and who stays together, so read these contacts as a way to talk about a relationship, not a forecast.