How to Calculate Your BaZi Chart (Step by Step)

Updated: August 2026 · Reading time: 7 minutes

To calculate a BaZi chart, you convert your birth year, month, day and hour into the Chinese lunisolar calendar, then assign each unit one Heavenly Stem and one Earthly Branch. The result is four pillars — eight characters in total — whose Five Element balance becomes the basis of the reading. The full system is a lifetime of study, but the calculation itself follows a fixed, repeatable process.

Step 1. Gather your birth data

You need four things: your birth date, birth time (the hour pillar changes every two hours), birth place or time zone, and your gender (needed for the Luck Cycle direction). If you do not know the hour, the chart can still be built with an unknown hour pillar.

Step 2. Convert to the Chinese lunar calendar

BaZi runs on the Chinese lunisolar calendar, not the Gregorian one. A solar date maps to a lunar month and day, and the year changes at Li Chun (Start of Spring, around 4 February), not on 1 January. This is why two people born in the same Gregorian year can have different year pillars.

Step 3. Find the year pillar

The year pillar is the Heavenly Stem and Earthly Branch of the Chinese solar year of your birth. The 10 stems and 12 branches cycle together, so the same stem-branch pair returns every 60 years — this is the famous 60-year cycle.

Step 4. Find the month pillar

The month pillar is determined by the 12 solar terms that divide the Chinese year, not by the 1st of each lunar month. Each month belongs to a branch, and the stem depends on the year's stem. This is the most technical step — the one where manual calculators most often slip.

Step 5. Find the day pillar

The day pillar is a continuous count of days in the Chinese calendar, independent of month boundaries. It is the pillar that carries your Day Master (日主) — the element that represents you and the anchor of the whole reading.

Step 6. Find the hour pillar

Each two-hour block of the day has one branch (子 Zi = 23:00–01:00, 丑 Chou = 01:00–03:00, and so on). The hour's stem depends on the day's stem. A birth time of 14:30, for example, falls in the 未 Wei hour (13:00–15:00).

Step 7. Read the element balance

Once you have the eight characters, translate every stem and branch into its element:

A chart where one element dominates — or where your Day Master has no support — explains a lot about your energy, health and decision style. Balancing those elements is what BaZi advisors work with.

Worked example

For a man born 15 May 1990 at 14:30, the calculation produces: year 庚午 Geng-Wu, month 辛巳 Xin-Si, day 庚辰 Geng-Chen, hour 癸未 Gui-Wei. His Day Master is 庚 Geng (Yang Metal). Counting elements, Fire is strong (three pillars join a Fire combination), Metal is his own element, Earth supports Metal, Wood is weak and Water scarce — a chart that reads as "strong metal refined by fire", suited to leadership roles but prone to rushing decisions.

Calculate your own chart in seconds

Doing this by hand takes practice and a reliable lunar calendar. Our calculator handles the solar-term boundaries, the 60-year cycle and the element counts automatically, then adds your Luck Cycles (大运) and a Zi Wei Dou Shu overview on top.

Frequently asked questions

Do I need my exact birth time to calculate BaZi?

For a complete chart, yes — the hour pillar changes every two hours. Without it, you still get the year, month and day pillars, which is about 90% of the chart.

Why is my BaZi year different from my Chinese zodiac year?

BaZi switches years at Li Chun (around 4 February), while zodiac animals are often counted from Chinese New Year. Born in January? Your pillar may be the previous year's.

What is the 60-year cycle in BaZi?

The 10 Heavenly Stems and 12 Earthly Branches combine into 60 unique pairs before repeating. This 60-year cycle structures both the year pillars and the Luck Cycles.

Which pillar represents me?

The Day Pillar, specifically its Heavenly Stem — the Day Master. It represents your core nature; the other pillars show the environment around you.

Can I calculate BaZi for a time before I was born, like for ancestors?

Yes, the calculation works for any date in the Chinese calendar, which is why family charts are sometimes read to understand inherited tendencies.

Continue learning: What is BaZi? · BaZi vs Western astrology · Free BaZi reading