However, if the phase changed close to your birth time, the date alone may give an incomplete answer. Someone born shortly before a First Quarter Moon and someone born shortly after it technically arrive at different points in the cycle, even if their birth certificates display the same calendar date.
Your location is less important for identifying the physical lunar phase than your exact moment of birth, because the Moon phase exists globally at the same instant, although local dates and clock times vary by time zone. Your location remains essential for calculating the houses, rising sign, and the rest of the birth chart accurately.
Calculate the Sun–Moon Angle Yourself
To calculate your natal Moon phase manually, you need the zodiac degree of your Sun and Moon.
Each zodiac sign occupies 30 degrees of the 360-degree zodiac:
- Aries begins at 0 degrees.
- Taurus begins at 30 degrees.
- Gemini begins at 60 degrees.
- Cancer begins at 90 degrees.
- Leo begins at 120 degrees.
- Virgo begins at 150 degrees.
- Libra begins at 180 degrees.
- Scorpio begins at 210 degrees.
- Sagittarius begins at 240 degrees.
- Capricorn begins at 270 degrees.
- Aquarius begins at 300 degrees.
- Pisces begins at 330 degrees.
Convert the Sun and Moon positions into absolute zodiac degrees, subtract the Sun’s position from the Moon’s position, and add 360 if the answer is negative.
For example, imagine that your Sun is at 18 degrees Cancer and your Moon is at 3 degrees Libra.
Cancer begins at 90 degrees, so an 18-degree Cancer Sun equals 108 degrees.
Libra begins at 180 degrees, so a 3-degree Libra Moon equals 183 degrees.
Subtract the Sun from the Moon:
183 − 108 = 75 degrees.
A 75-degree separation falls within the Waxing Crescent phase.
The eight-phase system usually divides the 360-degree cycle into sections of approximately 45 degrees:
| Sun–Moon angle | Natal Moon phase | Main developmental theme |
| 0° to under 45° | New Moon | Instinct and beginning |
| 45° to under 90° | Waxing Crescent | Faith and emergence |
| 90° to under 135° | First Quarter | Action and challenge |
| 135° to under 180° | Waxing Gibbous | Refinement and preparation |
| 180° to under 225° | Full Moon | Awareness and relationship |
| 225° to under 270° | Disseminating Moon | Sharing and interpretation |
| 270° to under 315° | Last Quarter | Reorientation and revision |
| 315° to under 360° | Balsamic Moon | Completion and release |
Different astrologers occasionally use slightly different names, orbs, and boundary rules, particularly when a birth falls extremely close to a phase change. A chart at 44 degrees and a chart at 46 degrees do not represent two people from unrelated emotional planets, so it is sensible to read both adjoining phases when you are born very close to a boundary.
Waxing and Waning: The First Big Distinction
Before we explore all eight phases, it helps to understand the difference between waxing and waning.
