How to use a BaZi calculator
Enter a supported record, resolve DST ambiguity, and read warnings without manufacturing precision.
Free BaZi Calculator
Generate your Four Pillars, Day Master, Five Elements, Ten Gods, Hidden Stems, and Luck Pillars. Free and no sign-up required.
FreeNo sign-upPrivate in your browser
Birth record
Gregorian calendar · Lunar input coming later
Advanced calculation settingsCurrent: mw-standard-v1Open
- Year boundary
- Exact Li Chun instant
- Month boundary
- Exact twelve Jie instants
- Luck start
- Three real days equal one year
Different BaZi schools may use different time rules. MingWeave records the method used for every chart.
No account. No server-side birth record.Static data loads from MingWeave; the chart is calculated in this browser.
How this BaZi calculator works
BaZi, also called Four Pillars, maps a Gregorian birth record into four stem-and-branch pairs. Year and Month follow solar-term boundaries; Day and Hour depend on the resolved working clock and the selected day-boundary convention.
MingWeave combines historical IANA time-zone data, exact solar-term instants, a versioned calculation engine, and a named Method Profile. The goal is a reproducible chart whose assumptions can be inspected without presenting traditional interpretation as scientific proof.
Birthplace, historical time zones, and True Solar Time
Birthplace resolves the historical local UTC offset and daylight-saving rules for the recorded clock time. Longitude is also needed if you choose True Solar Time. A present-day offset can be wrong for an older birth record, so the physical instant is resolved before any pillar is calculated.
True Solar Time is optional. MingWeave first resolves the real UTC instant, then applies longitude and a versioned equation-of-time correction to the working clock. That correction can affect Day or Hour near a boundary; it does not move the physical Li Chun or monthly Jie instant used for Year and Month.
Day Master, Ten Gods, Hidden Stems, and Five Elements
The Day Master is the Heavenly Stem of the Day Pillar. It provides the reference for Ten Gods relationships. Earthly Branches expand through a published Hidden Stems table, and each visible or hidden stem keeps its element, polarity, and relationship traceable.
The Five Elements display is a structural occurrence summary under MingWeave’s declared unweighted model. It is not a health measure, personality diagnosis, Strong/Weak verdict, or recommendation for a remedy. More elaborate traditional interpretations require additional assumptions that P0 does not collapse into one score.
Luck Pillars and why calculators can disagree
Luck Pillars are ordered decadal stem-branch sequences anchored to the Month Pillar. Direction follows the published traditional calculation rule, while starting age is calculated separately from the time distance to the relevant Jie solar term. Unknown inputs reduce timing precision instead of being silently invented.
Different calculators may disagree because they resolve historical time zones differently, use another Li Chun or monthly Jie boundary, enable solar-time corrections, change the day at 23:00 rather than midnight, or apply another Luck Pillar convention. Compare the method and trace before comparing interpretations.
Unknown birth time, privacy, and interpretation limits
When birth time is unknown, MingWeave returns a partial three-pillar chart, omits the Hour Pillar, and identifies fields whose value or timing cannot be supported. It does not substitute noon, midnight, or another convenient clock value just to make the chart look complete.
Birth inputs and personalized chart output stay in browser memory. The built-in copy and PNG export omit the source birth record. BaZi content is provided for cultural exploration and self-reflection, and should not be used as medical, legal, financial, safety, or other high-stakes advice.
BaZi calculator FAQs
What is BaZi or Four Pillars?
BaZi is a traditional system that represents a birth record with Year, Month, Day, and Hour stem-branch pairs. MingWeave calculates that structure and keeps interpretation separate from scientific or professional claims.
Why does birthplace matter?
Birthplace resolves the historical IANA time zone and UTC offset for the recorded local clock. Longitude is also required when True Solar Time is enabled.
What is True Solar Time in this calculator?
It is an optional working-clock correction based on longitude plus a versioned equation-of-time model. It can change Day or Hour near a boundary, while Year and Month still compare the physical birth instant with solar terms.
What do Day Master, Ten Gods, Hidden Stems, and Five Elements mean here?
They are deterministic chart structures derived from the pillars and published rule tables. The Day Master is the Day Stem; Ten Gods are Day-Master-relative relationships; Hidden Stems expand branches; Five Elements summarize structural occurrences under the declared model.
How are Luck Pillars calculated?
The Month Pillar anchors an ordered forward or reverse sexagenary sequence. Direction uses the published traditional category rule, while starting age is calculated separately from the exact duration to the relevant Jie solar term.
Why can another BaZi calculator disagree?
Common causes include historical time-zone handling, exact solar-term data, True Solar Time, midnight versus 23:00 day boundaries, place precision, and Luck Pillar conventions. MingWeave exposes its Method Profile and trace so those differences can be audited.
What if I do not know my birth time, and is my data private?
MingWeave returns a three-pillar result and marks time-dependent fields as unknown. Birth details and chart output remain in your browser; no account or server-side chart storage is used in P0. Interpret the chart as a cultural framework, not a factual verdict.
Continue learning
Trace the rules behind your result.
Why calculators disagree
Compare historical time zones, solar terms, time basis, and day-boundary conventions layer by layer.
Find your Day Master
Locate the Day Stem and use it as the transparent reference for Five Element and Ten Gods relationships.
For cultural exploration and self-reflection only. Read the full disclaimer and privacy boundary.