Full-chart synastry
See the conversation
between two charts.
Enter two birth records to compare the reliable chart factors available for each person. Exact times unlock Rising, MC, Moon, and house overlays; unknown-time mode omits those time-sensitive points. This is a map for conversation—not a compatibility score.
How to read a synastry chart
Aspects are a conversation starter.
Synastry compares the planets and angles in two birth charts. A conjunction brings two themes together; a trine or sextile can show where a shared rhythm is easier to access; a square or opposition can name a difference that needs more translation. None of those labels is a pass-or-fail score. They are simply a way to put specific words around dynamics you may already recognize.
With known times, this calculator compares Sun through Pluto plus Rising for both people. If a time is approximate, choose a declared range and the calculator tests every valid local minute inside it, then labels time-sensitive factors Stable or Boundary-sensitive. If a time is unknown, it keeps the slower planetary layer but omits that person’s Moon, Rising, MC, and house frame from exact synastry math; the result then shows the Moon’s 00:01–23:59 local-date range and checks whether each possible Moon contact survives the whole range, only part of it, or none of it. The five major aspect families use tighter orbs for slower outer-planet contacts. House overlays remain directional, and planets within 2° of a receiving cusp get a boundary caution without being reassigned.
Read the synastry aspect library Build the relationship midpoint chartSynastry calculator FAQ
Why are some aspects not shown?
The calculator includes Sun through Pluto plus Rising but limits the aspect layer to conjunction, sextile, square, trine, and opposition with focused orbs. Slower outer-planet contacts use tighter limits so generational placements do not overwhelm more specific contacts.
Can I use approximate or unknown birth times?
Yes. For an approximate time, choose ±15 minutes, ±30 minutes, ±1 hour, ±2 hours, or a custom range. The calculator scans every valid local minute in that interval and marks tested Rising, Midheaven, Moon, synastry, and overlay factors Stable or Boundary-sensitive. Unknown-time mode omits Moon, Rising, Midheaven, and that person’s houses from exact calculations, preserves the slower-planet layer and any valid receiving-house direction, shows the Moon’s possible civil-day range separately, and promotes only Stable or Conditional Moon contacts into the uncertainty panel.
Where does my report go?
The calculation stays in your browser. It is saved only when you press Save this report, using storage on this device.