BaZi Natal

Method精度

Precise to a tenth of a second.

A BaZi chart is only as good as its timing. Here is what we compute, and how we checked it.

< 0.1 s
Our solar-term error (NASA JPL DE440)
55 s
Largest error found in two widely used open-source libraries
1 in 60
Births with the wrong month pillar in one of them

Solar-term error, 1900–2049

SourceAverageWorst case
This calculator (JPL DE440)< 0.05 s0.05 s
lunar-javascript0.7 s2.9 s
sxtwl, 1900–19990.6 s3.3 s
sxtwl, 2000–204918.9 s54.9 s

0 / 1,800

At the boundary

Month pillar checked seconds either side of every solar term from 1900 to 2049. One library got 37 wrong within 2 seconds.

0 / 100,000

Full charts

Year, month, day, hour and luck pillars compared with lunar-javascript on random birth times.

From your clock to the Sun

  1. 01Clock timeAs written on the birth certificate
  2. 02Time zoneFull history of offsets and daylight saving
  3. 03Universal timeThe exact instant of birth
  4. 04LongitudeLocal mean time at your birthplace
  5. 05Equation of timeUp to ±16 minutes over the year
  6. 06True solar timeUsed for the day and hour pillars