Four pillars
Year, month, day and hour pillars in Heavenly Stem and Earthly Branch form, together with the true solar time they were derived from.
Free Four Pillars calculation
Start with the recorded moment.
Enter the local date, clock time and birthplace. The result will show the historical time-zone conversion, true solar time and every pillar before any report is offered.
Selected before calculationAnnual Timing BlueprintYou will still see the complete free result before checkout.
1Birth details
2Free chart
3Optional report
What the free result includes
The free chart is the real calculation, not a preview.
The pillars shown after you submit are the same ones a paid PDF would be generated from. Nothing in the calculation is held back to force a purchase, and no account or email is required.
Day Master and balance
The day-pillar stem, plus a Five-Phase distribution using this site's published weighting of visible stems, hidden stems and seasonal support.
Visible Ten Gods
The relationship each visible stem forms with your Day Master, each linked to a plain-English guide. Browse the Ten Gods.
How the time conversion works
Five steps, all of them stated
You enter local clock time
Use the time as it was recorded where the birth happened. Birth time is optional; if it is unknown, mark it unknown and the hour pillar is omitted rather than guessed.
Local civil time is resolved to UTC
The entered time is interpreted through its IANA time-zone identifier, so the historical UTC offset and any daylight-saving rule that applied on that date are handled from time-zone data. Do not subtract an hour yourself — that would apply the correction twice.
UTC becomes true solar time
The calculator adds roughly four minutes per degree of birthplace longitude east of Greenwich, subtracts for west longitude, then applies an equation-of-time approximation for the date.
The pillars are derived
The year changes at Li Chun rather than Lunar New Year, month boundaries follow the twelve Jie solar terms, and the day changes at 23:00 unless you choose civil midnight. A chart close to any boundary shows a visible warning.
The result is auditable
Each chart records its algorithm version, applied offset, longitude correction, equation-of-time correction and boundary notes, so the output can be checked later. Read the full methodology.
Where results differ between tools
Conventions this calculator uses
Four Pillars schools disagree on several rules. Rather than presenting one as universal, the calculator states its choice so a mismatch with another site can be located instead of guessed at. If your chart here differs from one you were given elsewhere, this guide walks through the five conventions that cause it.
| Question | This calculator | Also used elsewhere |
|---|---|---|
| Year boundary | Li Chun solar term | Lunar New Year |
| Month boundary | Twelve Jie solar terms | Lunar month |
| Day boundary | 23:00 Zi hour by default, civil midnight optional | Civil midnight only |
| Time standard | True solar time from IANA offset, longitude and equation of time | Clock time as written |
| Unknown birth time | Hour pillar omitted | Assumed noon or midnight |
Privacy
A calculated chart stays private to your session.
Birth details are collected only after explicit consent and encrypted at rest. Unpaid chart data is scheduled for deletion after 24 hours, and a delete control appears on the result page. Individual result pages are excluded from search indexing.
Questions
About the free calculator
Is the BaZi calculator free?
Yes. Calculating the chart and viewing the four pillars, the Day Master, the Five-Phase balance and the visible Ten Gods costs nothing. The optional paid PDF reports add a longer editorial interpretation and timing prompts built from the same stored calculation.
Do I need an account or an email address?
No. The chart is tied to your browser session, there is no account system, and no email is required to see a free result.
Can I calculate a chart without knowing my birth time?
Yes. Mark the time unknown and the hour pillar is omitted rather than assumed. The year, month and day pillars are still produced, and the result states which readings depend on the missing hour.
Do I need to adjust for daylight saving myself?
No, and you should not. The entered local time is resolved through IANA time-zone data, which already applies the historical offset and any daylight-saving rule in force at that place and date. Subtracting an hour manually would apply the correction twice.
Why does another site give me a different chart?
The usual causes are a different day-boundary rule at 23:00, a different treatment of the Li Chun year boundary, or one tool using clock time where another uses true solar time. This site publishes the conventions it uses so the difference can be identified rather than guessed at.
What happens to my birth data?
It is collected only after explicit consent and encrypted at rest. Unpaid chart data is scheduled for deletion after 24 hours by default, and you can delete a chart yourself from the result page at any time.
A calculated chart is a traditional symbolic framework for reflection. It is not a scientific assessment, a medical or psychological service, or a prediction of future events.