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Synastry Chart Calculator

Enter two sets of birth details to see how your charts interact — aspects, compatibility scores, and a midpoint composite.

Person A

Pick the closest 5-minute slot. Search by typing e.g. "10:35p" or "22:35".

Use romanized city names (e.g. Tokyo, not 東京). For renamed cities use the current name (Mumbai, not Bombay). Pick from the list to lock in coordinates and timezone.

Person B

Pick the closest 5-minute slot. Search by typing e.g. "10:35p" or "22:35".

Use romanized city names (e.g. Tokyo, not 東京). For renamed cities use the current name (Mumbai, not Bombay). Pick from the list to lock in coordinates and timezone.

What is synastry?

Synastry is the comparison of two natal charts to see how the planets in one person's sky interact with the planets in another's. Tight aspects between luminaries (Sun, Moon), inner planets (Mercury, Venus, Mars), and chart angles reveal real relational dynamics — chemistry, communication, conflict, and long-term potential.