Moon phase calculator
Find the exact Moon phase on your birthday — or any date — with its illumination and Moon sign.
Moon phase by date
Enter any date to see the Moon phase, illumination and Moon sign.
The Moon moves through eight phases in about 29.5 days, from New Moon to Full Moon and back. The phase you were born under colours how you experience emotions, instinct and inner rhythm.
This calculator uses the Swiss Ephemeris — the same high-precision engine used by professional astrologers — to find the exact Moon phase, its illumination and the zodiac sign the Moon was in on any date.
Frequently asked questions
What does the Moon phase at birth mean?
The birth Moon phase describes your emotional style and how you instinctively react. It adds nuance to your Moon sign and your wider birth chart.
Do I need my birth time?
No — the Moon phase is calculated from the date. The exact time only slightly shifts the illumination and, near a cusp, the Moon sign.
How accurate is it?
Positions are computed with the Swiss Ephemeris to arc-second precision, the standard used by professional astrology software.