Birth details

The four pillars are calculated from a civil birth date, an optional birth time, and the timezone of the birth place. We do not collect a name, and nothing is sent to a server — the chart is calculated in your browser.

Birth date

Birth time Birth time unknown

Timezone of the birth place

Use this device’s timezone

Solar terms, which set the year and month pillars, are astronomical moments. The timezone places that instant on the correct side of 立春 and the month-change terms. Use the zone in effect at the birth place, not where you are now.

The hour pillar follows the two-hour 时辰. If the time is unknown, we omit that pillar and the note is less complete. On a date that contains a solar term, the year or month can also depend on the time of day.

Advanced: late 子时 (11:00 p.m. – 12:59 a.m.)

Day-pillar convention after 11:00 p.m. Default — keep the civil day’s pillar; the hour still uses 子时 of the next day (library sect 2) Advance the day pillar at 11:00 p.m. (library sect 1)

Schools disagree about whether the day pillar changes at 11:00 p.m. or at midnight. The default follows lunar-javascript sect 2. This only matters if the birth time is in that window.

View a sample chart

The sample uses a published library test date (23 December 2005, 8:37 a.m., Asia/Shanghai). It is a calculation check, not a personal reading.