Born outside UTC+8, in the Southern Hemisphere or living abroad: how is my chart calculated?
Your BaZi (八字) chart is calculated from where and when you were born: the clock time at your birthplace, read in that place's own time zone and then converted to local true solar time. Where you live now does not change it.
| What sets your chart | Birth date, birth clock time and birth city |
|---|---|
| What does not | Where you live now, or your phone's time zone |
| Clock time to world time | Your birth city's time-zone history (IANA zone), including daylight saving in force that day |
| World time to solar time | Birth longitude (4 minutes per degree) plus the equation of time |
| Year and month boundaries | Lichun (立春) and the 12 jie (節) solar terms: astronomical moments, the same instant everywhere |
| Day and hour pillars | Local true solar time at the birthplace; the day turns at 23:00 (start of the Zi hour, 子時) |
| Southern Hemisphere | Same rules as the north: no seasonal flip of the month pillar |
| Daily Joss, personal day, Joss Timing | Where you are now (or where the event happens) |
Living abroad does not change your chart
A chart records one moment at one place. Someone born in Guangzhou who now lives in Auckland or London keeps the same four pillars: enter the city you were born in.
Step 1: your clock time, in your birthplace's time zone
We turn the time on the birth certificate into world time (UTC) with the birth city's time-zone history, so daylight saving applies only where and when it was in force. Mainland China, for example, used summer time from 1986 to 1991. A birth at 12:00 on May 1, 1988 in Beijing was at UTC+9, not UTC+8. The profile gives a true solar time of 10:48, a correction of −71.5 minutes: about 60 for summer time, 14.4 because Beijing (116.40°E) lies west of the 120°E meridian that UTC+8 is set on, and the equation of time (+2.9 minutes that day) pulling the other way. Pillars: 戊辰 丙辰 丙辰 癸巳.
The same goes for summer time in Hong Kong and Taiwan (some years up to 1979), Europe, North America, Australia and New Zealand.
Step 2: from clock time to local solar time
Traditional charts read the hour from the sun: every degree of longitude is four minutes of solar time. Auckland (174.76°E) sits about 21 minutes behind the 180° meridian its zone is based on; in summer, New Zealand clocks also run an hour ahead. A birth at 09:00 on January 10, 1990 in Auckland therefore has a solar time of 07:31 (−88.2 minutes, including −7.2 for the equation of time). That is still the Chen hour (辰時, 07:00–09:00), so the hour pillar is 庚辰.
Solar terms happen at the same instant everywhere
The year changes at Lichun and each month at a jie solar term. These are moments when the sun reaches a set point on the ecliptic, one instant worldwide. Lichun 2027 is at 09:46 Hong Kong time (UTC+8) on February 4, 2027, which is 14:46 the same day in Auckland and 01:46 in London.
So a baby born at noon on February 4, 2027 in Auckland arrives before Lichun and has the pillars 丙午 辛丑 甲寅 己巳, still in the 丙午 Horse year. A baby born at noon that day in Hong Kong arrives after it and has 丁未 壬寅 甲寅 庚午, the 丁未 Goat year. Time zone matters most for births on a solar-term day and births near 23:00 or midnight, when the day pillar can change.
Born in the Southern Hemisphere
We follow mainstream practice: the month pillar follows the solar terms, as in the north, with no seasonal flip. The Auckland noon baby above was born in high summer, yet its month branch is 丑 (Chou, Ox), a winter month in the classical table. A minority "southern hemisphere school" swaps each month branch with the one six places away (寅 Yin with 申 Shen, and so on) to match local seasons. We do not use it, so its readings can show a different month pillar.
If your city is not in the list
The profile has 156 built-in birth cities, including Sydney, Melbourne, Brisbane, Perth, Adelaide, Canberra, Gold Coast, Hobart, Auckland and Wellington. If yours is missing, pick the nearest listed city in the same time zone (each degree of longitude is four minutes), or choose "Other: enter longitude and time zone" and type your birthplace's longitude (east +, west −) and its time-zone name, such as Pacific/Auckland or America/Toronto. A plain number such as 12 also works but cannot apply daylight saving.
If you do not know your birth time
Tick "I don't know my birth time" and we compute three pillars (year, month, day) and leave out the hour pillar. The day pillar then assumes a daytime birth. On a solar-term day the month can also depend on the hour.
What uses where you are now
Daily Joss and your personal day use the time zone of the device you are using. Joss Timing uses the city where the event happens. The public almanac pages are printed for Hong Kong time (UTC+8), like a printed Tong Shu.
How askjoss computes it
Time zones and daylight saving come from the standard IANA time-zone database; solar terms from an astronomical model, accurate to about two minutes. Full notes, including every simplification, are on How we calculate.
Common misconceptions
- "I should use my current city." The chart is fixed at your birthplace.
- "Convert my birth time to Beijing time first." No: enter the local clock time where you were born; we apply the time zone.
Your Joss Profile shows the solar time it used.
Related: What is BaZi? · Day Master · Five elements · Tong Shu almanac · Da Liu Ren · Qi Men Dun Jia · Zodiac clashes (Tai Sui)
Frequently asked questions
Born outside UTC+8, in the Southern Hemisphere or living abroad: how is my chart calculated?
From your birth city and the clock time there, converted with that city's time-zone history (including daylight saving) and then to local true solar time. Solar terms are one instant worldwide, we do not flip the month pillar south of the equator, and where you live now does not change your chart.
I was born in China and now live in New Zealand. Does my chart change?
No. Enter your birth city in China and the local clock time; the chart is the same wherever you live. Daily Joss uses your current time zone.
Does daylight saving time affect my BaZi?
It can move the hour by one. Choosing your birth city applies the rules in force there on your birth date, such as China's summer time of 1986 to 1991.
Should the month pillar be reversed for the Southern Hemisphere?
A minority school swaps the month branches by six to match local seasons. askjoss follows mainstream practice: the same solar-term months everywhere.
askjoss presents Chinese metaphysics as cultural tradition and a tool for self-reflection. It is not medical, legal, financial or psychological advice, and no reading can promise an outcome.