Born overseas: which time does your chart use?
The local clock time at the place you were born, corrected to the sun at that longitude. Not the time in your family's country of origin, and not Beijing time unless you were born near that meridian.
The mistake worth avoiding
A common instruction in Chinese metaphysics is to convert everything to Beijing time. It comes from a period when that was the practical way to standardise, and it is wrong for anyone born outside China.
The hour branch depends on where the sun was above you. Someone born in Vancouver at 08:00 was under a morning sun in Vancouver. Converting that to Beijing time produces a number with no relationship to the sky they were born under.
What to gather
- The city, not the country. Longitude is what matters, and countries are wide.
- The clock time as recorded locally, from the birth certificate where possible.
- The date, so historical daylight saving and any offset change can be resolved.
With those three, the conversion is arithmetic. Without the place, it is a guess.
Same clock, different chart
| Born 15 June 1990, 07:30 local, UTC+8 | Singapore | Hong Kong |
|---|---|---|
| True solar time | 06:25 | 07:06 |
| Hour pillar | 辛卯 | 壬辰 |
Two cities in the same time zone, roughly 2,500 kilometres apart, and a different hour pillar from an identical clock reading.
Meridian asks for your birth city and resolves the rest, including whether summer time was in force there that year. Diaspora charts are the case most tools handle worst, and they are common in Hong Kong, Singapore, Malaysia and everywhere Chinese families have settled. Getting them right is not an advanced feature. It is the baseline.
If the record is thin
- City unknown, country known. A chart can be built on an approximate longitude, and should say so.
- Hospital in one town, family in another. Use the hospital. The chart follows the birth.
- Time zone changed since. Historical offsets are what matter, not today's.
Sources
- National Library Board Singapore, the 1982 time zone change
- IANA Time Zone Database, historical offsets and transitions
Related
- Why do two BaZi calculators give you different charts?
- Should a BaZi chart use clock time or true solar time?
- Does daylight saving change your hour pillar?
Cast a chart from your birth city, not your time zone
Worked example computed by Meridian's chart engines on 1 August 2026. The engines are deterministic, so the same input returns the same chart.
This page explains calculation conventions. It does not interpret a chart and is not advice.