Bazi Diff

One birth.
Four answers.

Two BaZi apps, two different charts? Compare four calendar conventions side by side and see exactly which rule changed your Four Pillars.

Compare your chart

Free comparison · No account needed

24-hour dial highlighting the late Zi hour from 23:00 to midnight
23:40 in New YorkFeb 4, 1994 · Worked example 2 pillars differ
Four calendar conventions Birth years 1900–2100 Birth data stays on your device

Find the difference.

Enter a birth time once. The table shows the year, month, day and hour pillars for each convention.

Birth details

Birth date

Birth time 24-hour clock

Worked example · New York

Four Pillars comparison

Year, month, day and hour pillars by calendar method
Pillar Almanac Early-Zi Solar-term instant True solar

Why charts disagree.

Calendar conventions can move a pillar at a boundary. Knowing which convention an app uses is more useful than picking a winner.

The free comparison covers the first four boundary types below. Daylight saving and luck cycles are part of the planned report.

This is a calendar comparison. It offers no fortune telling, predictions or life advice.

  1. Where the year begins

    Four Pillars uses Li Chun, while some charts start the year at Lunar New Year. The four methods here use Li Chun, with day and instant variants.

  2. Solar-term date or instant

    Some conventions switch the month or year on the calendar day of a solar term. Others wait for its precise time.

  3. The late Zi hour

    Midnight and 23:00 are both established day boundaries. Even the calendar library’s maintainers leave that choice to the practitioner.

  4. Clock time or solar time

    Longitude can shift a birth time across a two-hour branch or a solar-term boundary. This comparison uses longitude only.

  5. Daylight saving

    China observed seasonal clock changes in 1986–91. Most U.S. regions still do. This tool uses fixed offsets and does not adjust for DST.

    Report in preparation

  6. Luck-cycle direction and start

    Da Yun calculations can follow different direction and starting-age rules. Luck cycles are outside the free pillar comparison.

    Report in preparation

Go deeper on the boundary.

The full four-method comparison and explanations are free. A $4.90 one-time report is in preparation for cases that need a closer look.

  • Which boundary risks apply to your chart
  • Da Yun starting age with early and late Zi conventions
  • Minute-by-minute solar-time boundary analysis
  • Practitioner checklist and daylight-saving verification

Daylight-saving verification is planned for the report. It is unavailable today.