Chart methods and reference
Why do BaZi charts differ? Check inputs, time and boundary rules
Find which pillar differs before comparing interpretations. Different results may come from input mistakes, different time references or different conventions. An interpretation that feels familiar does not establish which calculation is correct.
Use your birth details, then compare your chart with this guide. Basic results need no login.
Calculate my BaZi chart1. Compare the original inputs first
Align the Gregorian date, 24-hour time, longitude, time-zone offset and daylight-saving setting. For lunar input, also align the year, month, day and leap-month flag: a leap fifth month is a different month from the ordinary fifth month. A hospital clock record and a remembered two-hour birth period are different evidence. Keep a snapshot of the inputs and change one setting at a time.
2. Use the differing pillar to narrow the search
If only the hour differs, check time conversion and two-hour boundaries first. If the day and hour differ, check the entered date, solar-time date rollover and day-boundary convention. A changed day stem also changes the reference for every Ten God label. If only the month differs, check the precise jie boundary. Near Start of Spring, both year and month can change together. These are diagnostic clues; several issues may overlap.
3. Four Pillars do not all use the same clock reference
This project changes the year at the instant of Start of Spring and the month at the twelve jie boundaries, comparing absolute instants. The day and hour use corrected true solar time, with the day changing at solar-time midnight. Longitude correction changes the local solar clock, not the absolute instant of a solar term. For international births, check the actual time-zone support of the tool; a Beijing-time input must not silently be treated as local time.
Use your birth details, then compare your chart with this guide. Basic results need no login.
Calculate my BaZi chart4. Test boundaries instead of guessing accuracy
The first table comes from the project’s Beijing standard-time teaching entry point, without longitude or equation-of-time correction. It isolates the rule: 22:59 to 23:00 changes the hour; the day changes at 00:00. A calculator that changes the day at 23:00 may use a different convention; inspect how it also derives the hour stem. The second table isolates year and month boundaries. Real birth charts apply solar-time correction, so clock 23:00 alone is insufficient.
| Time (UTC+08:00) | Year pillar | Month pillar | Day pillar | Hour pillar |
|---|---|---|---|---|
| 2024-06-15 22:59 | Jia Chen | Geng Wu | Geng Xu | Ding Hai |
| 2024-06-15 23:00 | Jia Chen | Geng Wu | Geng Xu | Bing Zi |
| 2024-06-16 00:00 | Jia Chen | Geng Wu | Xin Hai | Wu Zi |
| Solar term | Time (UTC+08:00) | Year pillar | Month pillar |
|---|---|---|---|
| Start of Spring | 2024-02-04 16:27:06 | Gui Mao | Yi Chou |
| Start of Spring | 2024-02-04 16:27:07 | Jia Chen | Bing Yin |
| Awakening of Insects | 2024-03-05 10:22:44 | Jia Chen | Bing Yin |
| Awakening of Insects | 2024-03-05 10:22:45 | Jia Chen | Ding Mao |
5. Identical pillars can still produce different readings
For different Ten God labels, compare the Day Master, aliases such as Seven Killings versus Indirect Officer, and whether hidden stems are shown separately. For different luck cycles, compare direction, time to the relevant solar term, conversion to starting age and age notation. Useful elements, strength and configurations involve further interpretation. Establish agreement in deterministic calculation before discussing interpretive differences.
A practical checking order
1. Confirm Gregorian or lunar input and the leap-month flag. 2. Confirm the clock time and legal time zone; overseas times need conversion to UTC+8 here. 3. Compare solar-time correction and longitude. 4. Compare the day boundary and Zi-hour rule. 5. Only then compare school-specific chart parameters. Change one setting at a time and record which pillar changes.