Find out what the moon looked like on the day you were born — and what it means.
Calculated from astronomical data. Spiritual meanings are cultural and for entertainment only.
The moon completes a full cycle from new moon to new moon in approximately 29.5 days — the synodic month. This cycle has been observed, tracked, and interpreted by cultures across history. The eight primary phases (new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, waning crescent) each occupy roughly 3–4 days of the cycle.
Determining the moon phase for any historical date requires knowing the reference point of a known new moon and counting forward in 29.5305882-day intervals. The algorithm this tool uses is accurate for dates from 1900 onwards, drawing on established lunar calculation methods used in astronomy software. The result is typically accurate to within a day, which is sufficient for most purposes given that phases themselves span several days.
In Western astrology, the moon phase at birth is considered part of the natal chart interpretation. The new moon is associated with beginnings, instinctiveness, and a subjective, internally-directed orientation. The full moon is associated with heightened awareness, culmination, and a tendency toward objectivity and external projection. The waxing phases between them are associated with growth, action, and accumulation. The waning phases are associated with dissemination, refinement, and release.
In many Indigenous and traditional cultures worldwide, lunar phases carry agricultural, ceremonial, and spiritual significance. These traditions vary considerably by culture and should be understood in their own contexts rather than blended with Western astrological interpretations.
No peer-reviewed research supports the hypothesis that the moon phase at birth influences personality or life outcomes. The associations described above are cultural and spiritual in nature, not scientific claims. This tool presents them as such.
Related: Numerology Life Path Calculator · Zodiac Compatibility · Birth Chart Summary