Calculator
Birth Chart Calculator
Click any number to see its inputs, formula and intermediate steps.
Reference Parameters
Saved references
- No saved references.
Centre numbers
Top left
Calculated: –
Center
Calculated: –
Bottom left
Calculated: –
Bottom right
Calculated: –
Birth Chart Summary
- Male Gua
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- Female Gua
- –
- Illumination (ILLU)
- –
- Lunar Month (LM)
- –
- Lunar Day (LD)
- –
- Moon Phase
- –
- Personal Element
- –
Your Personal Profile
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Chart
SE4
S9
SW2
E3
C5
W7
NE8
N1
NW6
South at top. Small numeral = Lo Shu base number.
Calculations & audit trail
Chart layer derivation
| Position | Centre | Source |
|---|---|---|
| Top left | – | – |
| Center | – | – |
| Bottom left | – | – |
| Bottom right | – | – |
Calendar boundaries
- Lunar Month: the 1-based ordinal of the most recent astronomical new moon among all new moons whose local civil date (birth time zone) falls in the Gregorian birth year. No month is assigned before that year's first new moon.
- Lunar Day: floor of exact elapsed days since that new moon, plus 1. No rounding before the floor.
- Gua & Nine Star Ki year: the year begins at the exact instant of Li Chun (Sun's apparent geocentric longitude = 315°, ≈ 4 Feb), compared in UTC — not 1 January and not Chinese New Year.
- Nine Star Ki month: solar months begin at the exact instants of the 12 jié terms (Sun at 315°, 345°, 15° … 285°); the Tiger month starts at Li Chun.