Enter your date and time of birth (solar calendar) and we compute the four pillars — year, month, day and hour — right away. No sign-up needed.
※ Solar dates only for now (lunar input is coming soon). Calculated on Korea Standard Time; true solar time correction for your birthplace longitude is applied in the full Saju report.
A Saju calendar writes each date in Ganji (干支) characters. Enter your date and time of birth and it gives the year, month, day and hour as two characters each — eight characters in all. Those eight are your Four Pillars.
People used to look this up in a thick book. Here you only enter your birth date and time and it comes out at once. Lunar or solar, either is fine.
Saju (四柱) means four pillars. The year you were born is the year pillar, the month the month pillar, the day the day pillar, the hour the hour pillar. Each pillar carries one Heavenly Stem on top and one Earthly Branch below — eight characters together.
There are ten Heavenly Stems (甲乙丙丁戊己庚辛壬癸) and twelve Earthly Branches (子丑寅卯辰巳午未申酉戌亥). The zodiac animal people usually talk about comes from these branches.
The month does not turn on the first of the month but on a solar term. In Saju a year begins at Ipchun, and a month changes at the moment a term such as Ipchun, Gyeongchip or Cheongmyeong enters.
So someone born on 3 February and someone born on 5 February may carry different year and month pillars even though it is the same calendar month. The exact moment the term enters has to be counted, and this page counts it.
Leave the hour pillar empty and read the other three. Not knowing the hour does not mean nothing can be read. The day pillar still comes out, and the day pillar stands for you, so it carries a good deal on its own.
Do not guess the hour, though. Two hours off and the hour pillar changes completely. If you do not know it, leaving it blank is the right thing.
Enter your birth date and time and the eight characters appear at once. There is no charge. You may print it and carry it with you.
To see how the eight characters work on one another, go to the full Saju analysis. The birthday star sign page shows how the same birthday fell differently from year to year.
As described above under "The eight characters of the four pillars," the twelve branch characters attach to years as well as days. The branch of your birth year is what we usually call the zodiac animal. We ran the birth dates of 281 Korean singers, actors and K-pop idols whose birthdays we could confirm through this page's own engine and counted how the year-branch (the animal) split out. In Saju, a year starts at Ipchun (the solar term, not January 1st), so anyone born before that year's Ipchun is counted under the previous year's animal — exactly as this page itself calculates it.
If the twelve animals came out perfectly even, each would have 23.4 people. In fact the most common was the Snake with 31, and the least common was the Dog with 17 — a 1.82-fold difference.
⚠ This is a statistic, not a reading of you. A 1.82-fold gap across 281 people does not mean the Snake favors a career in entertainment or that the Dog is rare among entertainers. A sample this size can spread that far by chance alone — we report what we counted and attach no reason to it.
On the compatibility page we grouped the branch of the birth day into four trine sets. Here we apply the same trine grouping to the branch of the birth year (the animal) instead — and get different numbers. Perfectly even would be 70.25 people per set.
We attach no reason to this flip either. The day branch and the year branch are simply different counts produced by different mechanics — one accumulates by date, the other is the animal-year itself.
We counted the same 281 people along other axes too — by Western zodiac (Sun sign), Capricorn came out on top (see the zodiac distribution →), and grouping Saju day branches into trine sets, the Fire set came out on top (see it on the compatibility page →). The same people can show a different "most common" group depending on which axis you count by.
In Saju, a month does not change on the 1st — it changes the instant a solar term begins, the same boundary described at the top of this page. We ran the same 281 birthdates through this page’s own calculation and counted how the twelve month branches split. Perfectly even would be 23.4 people per branch.
In practice the most common month branch was Rooster (酉) with 30 people, and the least common was Pig (亥) with 14 — a 2.14x gap. That is wider than the 1.82x gap we found earlier for the year branch (the zodiac animal).
⚠ This is a statistic, not a reading of you. We are only reporting that a 281-person sample showed a 2.14x gap — it does not mean being born in a Rooster month leads to anything. A sample this size can show a gap this large by chance alone.
The rule that a Saju year starts at Ipchun (around February 4), not January 1, applies to the year just as it does to the month. So someone born between January 1 and the day before Ipchun can have a birth-year zodiac animal that differs from the one Saju actually uses.
Running the same 281 people through this page’s own calculation, 30 of 281 (10.7%) had the two zodiac animals disagree — every one of them born between January 1 and the day before Ipchun. If your own birthday falls in January or early February, your commonly-known zodiac animal and your Saju zodiac animal may differ.
Splitting those 30 by month, 25 were born in January and 5 in early February (before Ipchun) — January dominates simply because the pre-Ipchun window within a calendar year (January 1 to around February 3) is shorter than the month of January itself.
You have your chart. What do these characters mean?
A Saju chart can be read once you know 22 Chinese characters. We are publishing Beomjin’s textbook Self-Saju vol. 1 chapter by chapter (in Korean).
Self-Saju vol. 1 contents (Korean) → Chapter 1: What is Saju? (Korean)