What is a synastry chart?
Synastry compares two people’s natal positions while keeping each birth chart distinct. A cross-chart aspect joins a planet in one person’s chart to a planet in the other. This tool displays the comparison as a wheel and tables; it does not assign a relationship score.
How to use this tool
- Create a birth profile for the first person, with their own date, local time and city.
- Use Add a second profile in the comparison area, or New chart, to create the second profile. Guests can keep both in local History; signed-in users can save them to their account.
- Choose the second person in the comparison field. Use Table or Aspects to read the named connections between the two profiles.
How to read a synastry comparison
Check the names attached to each layer before reading an aspect. Person A’s Moon to person B’s Saturn is a specific pairing; person A’s Saturn to person B’s Moon is another. Start with a few connections and keep their direction clear.
Look up each person’s natal chart separately when you need context for a position. Synastry adds the connections between those charts. If you want one combined midpoint chart instead of two distinct layers, use the composite tool. Neither technique can replace what you know about the people and their relationship.
Before interpreting the result
Unknown or approximate birth times reduce the reliability of angles and house placement, and may affect the Moon’s position. The comparison shows astrological geometry rather than a verdict about whether a relationship will succeed.
Common questions
Can I compare friends or family members?
Yes. Choose any two birth profiles you want to study. The calculator does not require a romantic relationship or a particular relationship type.
What if I do not know the second person’s birth time?
Use the unknown-time option for that profile. The working time is noon; avoid treating time-sensitive positions, houses or angles as an exact reading.
What is the difference between synastry and a composite chart?
Synastry preserves two natal charts and compares their positions. The midpoint composite calculates new positions halfway between matching planets in those two charts.