YOUR SKY ATLAS · TWO SKIES. A SHARED PERSPECTIVE.
Compatibility Calculator
Compare two birth charts with a two-ring synastry wheel and the major aspects between them.
How to Use This Calculator
- Select the birth date and enter the local time from a reliable record for each person. Choose the unknown-time option if needed.
- Search for the birthplace and select the matching city, region, and country.
- Select “Calculate Compatibility.” Review the calculated details before reading the interpretation.
Understanding Synastry
Synastry compares one person’s planets with another person’s planets and known angles. An aspect is a particular angular relationship between these positions. The same relationship can be supportive in one context and demanding in another, so this comparison offers discussion prompts rather than a relationship score.
Frequently Asked Questions
Can I compare charts without both birth times?
Yes. Unknown-time charts omit their houses and angles. We show the range of possible inter-chart orbs across each unknown local date and distinguish all-day aspects from time-dependent possibilities.
Does this predict whether a relationship will work?
No. Synastry is an astrological interpretation, not a measurement of relationship quality or a prediction of your choices. There is no compatibility percentage.
Calculation Method and Limitations
All tools share local Swiss Ephemeris calculations, tropical zodiac, and historical IANA time-zone conversion. Unknown times limit the precision of degrees, houses, angles, and aspects. Read the full method and limitations or review Source & License.