How Our Charts Are Calculated
Methods, schools and data sources behind every Destiny Atlas module.
Divination systems leave room for different conventions, which is why the same birth data can give slightly different charts on different sites. This page spells out exactly which rules Destiny Atlas follows, so you can check and compare. All results are for cultural study and entertainment only.
How is the BaZi (Four Pillars) chart calculated?
The year pillar changes at the exact moment of Lichun (Start of Spring). The month pillar changes at the exact moments of the twelve "jie" solar terms (Lichun, Jingzhe, Qingming, Lixia, Mangzhong, Xiaoshu, Liqiu, Bailu, Hanlu, Lidong, Daxue, Xiaohan), to the minute, using solar-term times from the open-source calendar library lunar-javascript. The day pillar follows the sexagenary day of the Gregorian date, and the hour stem is derived from the day stem with the traditional Five Rats rule (五鼠遁).
How do you handle births between 23:00 and midnight (the Zi hour)?
We use the common modern convention known as "late Zi hour stays with the same day" (晚子时归本日). For a birth at 23:00-23:59, the day pillar still follows the calendar date, while the hour stem is derived from the next day's stem, because the Zi hour opens the new day. Some traditional schools instead switch the day pillar at 23:00. If another tool shows a day pillar one day off, this convention is almost always the reason.
What if I was born on the day of a solar term?
We compare your birth time with the exact moment the term begins. Born before it, you still belong to the previous month; born after it, you belong to the new one. For example, someone born on Lichun day before the term starts still has the previous year's year and month pillars. If no birth time is given, the whole day is used.
How does the true solar time correction work?
It is applied only when you enter a birth city and turn on true solar time. The correction is the longitude offset (the difference between your birthplace's longitude and your time zone's standard meridian, 4 minutes per degree) plus the equation of time (the effect of Earth's elliptical orbit, using Spencer's approximation). The corrected time sets the hour pillar and can move the birth into the previous or next day.
How are luck pillars (Da Yun) ordered, and when do they start?
They run forward for a man born in a yang year or a woman born in a yin year, and backward for a man born in a yin year or a woman born in a yang year. The starting age comes from the number of days between birth and the next (forward) or previous (backward) jie solar term: three days count as one year and one day as four months. Each luck pillar then lasts ten years. Days are counted as whole days, so the start can differ by a few months from methods that count to the hour.
Is the Chinese zodiac sign based on Lunar New Year or Lichun?
When the full birth date is known (the BaZi year pillar, zodiac compatibility and name analysis), we use Lichun. The Chinese zodiac horoscope page asks only for a birth year and uses that year's animal. If you were born before Lichun (around 4 February), you traditionally belong to the previous year's animal, so enter the previous year there.
How is the ZiWei Dou Shu chart built?
ZiWei charts are generated with the open-source library iztro, which accepts Gregorian or lunar dates (including leap months) and maps birth time to the twelve two-hour periods. The twelve palaces, major and minor stars and the four transformations come from iztro; Destiny Atlas adds plain-language interpretation on top.
How is the Western birth chart (natal chart) calculated?
Planetary longitudes are computed with the open-source astronomy library astronomy-engine for your birth moment in Universal Time. The Ascendant comes from your birthplace's latitude, longitude and local sidereal time. Houses use the Whole Sign system: the Ascendant's sign is the first house and each following sign is the next house.
Are tarot, I Ching and oracle card readings random?
Yes. The tarot deck is shuffled before every draw, and each card has an even chance of appearing reversed. I Ching readings simulate the traditional three-coin method by default, throwing three coins for each line to set yin, yang and changing lines; you can also cast by numbers or enter the six lines yourself. Oracle cards are drawn at random from the chosen deck. Card and hexagram meanings are original plain-language commentary built on the traditional meanings.
How are strokes counted in Chinese name analysis?
The Five Grids (Heaven, Person, Earth, Outer and Total) use Kangxi Dictionary stroke counts. The last digit of each grid maps to one of the five elements to judge the Three Talents (三才) arrangement. Results are combined with your BaZi favourable elements and zodiac affinity.
Which numerology system do you use?
Western Pythagorean numerology. The Life Path number reduces the digits of your birth date; Expression, Soul Urge and Personality numbers come from the letters of your name. Master numbers 11, 22 and 33 are kept.
Should I take these results literally?
We calculate each system faithfully according to its common conventions, but divination is not scientific prediction. All results are for cultural study, self-reflection and entertainment, and are not a substitute for medical, legal, financial or other professional advice.