How to Calculate Your Six-Star Type

Six-Star Astrology runs on math, not vibes. Here is the math.

The system feels intuitive once you have your reading in hand — your star type, your polarity, your current phase of the twelve-year cycle. But under the friendly surface is a small, specific calculation done from two facts: the year you were born and the day you were born. This article walks through both halves of that calculation. By the end you will understand exactly what the calculator is doing on your behalf, and why the part that actually matters — the cycle phase — is the part you would not want to do by hand.

The two inputs

Every Six-Star reading needs exactly two pieces of input from you.

Your birth year decides your polarity — Plus or Minus. The polarity is read off the Chinese zodiac animal for the year, which repeats on a twelve-year cycle.

Your birth day decides your star base — one of Saturn, Venus, Mars, Uranus, Jupiter, Mercury. The base is read off the sexagenary calendar, a sixty-day rotation that has been used in East Asia for millennia.

Combine them and you get your Six-Star type. Six bases multiplied by two polarities gives twelve possible types — from Saturn-Plus through Mercury-Minus. Once you know which one you are, the cycle table can tell you what phase you are in for any given year.

Step 1: birth year and polarity

The first step is easy enough to do in your head. Take your birth year, divide by twelve, and look at the remainder. The remainder maps to a zodiac animal. Even-numbered remainders are Plus polarities; odd-numbered are Minus. The full table:

Born in 1990? 1990 divided by twelve is 165 with a remainder of 10. Year 10 is 午 (Horse), which is Plus. So if you were born any time in 1990, your polarity is Plus. Done. Half the calculation, sixty seconds of arithmetic.

One careful note: in traditional practice, the year boundary is the Lunar New Year (usually early February), not January 1. People born in January or very early February sometimes belong to the previous year's animal for astrological purposes. Most modern calculators handle this for you, but if you were born in that two-month window, double-check what the system assigns you before you trust the polarity.

Step 2: birth day and the sixty-day cycle

The second step is where the system starts being interesting. To find your star base, the calculator looks up the sexagenary day-stem-and-branch (干支) for your birth date.

The sexagenary calendar is one of the oldest active calendars in the world. It cycles every sixty days through pairs of one of ten "stems" and one of twelve "branches." Day one of the cycle is 甲子, day two is 乙丑, and so on through 癸亥, after which it returns to 甲子. Sixty consecutive days. No gaps, no leap-year corrections — it just runs.

Six-Star Astrology slices those sixty days into six equal groups of ten, and assigns each group to one of the six star bases:

To do this by hand you need a lookup table for the sexagenary day of your birth — most published Six-Star books include one, and the public Wikipedia entry for 六星占術 (Six-Star Astrology) has a working description of the same procedure. The math is not hard. The data is the inconvenient part. To compute the sexagenary day of any date you need either a calendar lookup or a Julian-day-number calculation, and most readers do not keep one of those in their head.

A worked example: May 15, 1990

Take a single birth date and run it all the way through.

Year step. 1990 mod 12 = 10. Year 10 is 午 (Horse). Polarity: Plus.

Day step. May 15, 1990 corresponds to day index 14 in the sixty-day sexagenary cycle. (You would need a lookup table for this in practice; trust the number for the worked example.) Day index 14 falls in the Venus group (10 – 19). Star base: Venus.

Combine them: a person born on May 15, 1990 is Venus-Plus.

That is the entire calculation. From your birth year you read polarity; from your birth day you read base; you concatenate the two. It is also one of the cases pinned by a unit test in this project's calculation suite, which means the same answer comes back every time the code is changed. (We test it because users notice when the math drifts.)

Why the AI version is better than doing it by hand

If your goal is just to know your star type, the calculation above is doable. It is also, frankly, the boring half of the system. Your star type is static — you were Venus-Plus the day you were born, you are Venus-Plus today, and you will be Venus-Plus on the day you die. It is a fixed label.

The interesting part of Six-Star Astrology is the part that moves: your current twelve-year cycle phase. That phase changes every year. It is what answers the practical question — is this a year to push or a year to rest, a year to plan or a year to consolidate? And computing the cycle phase from your star type and the current year is exactly the kind of multi-step lookup that humans get wrong and software gets right.

The AI reading does both calculations in under a second and then does the part the calculation does not give you: it interprets the result. Knowing you are Venus-Plus in your Stability year tells you almost nothing. Knowing what Stability usually asks of a Venus-Plus temperament — that is the reading. For a deeper read on how the twelve phases work, the twelve-year cycle explainer walks through every phase in order.

The arithmetic is the gateway. The interpretation is the door.

Skip the lookup tables

If you want your star type and your current phase computed from your birth date, in a few seconds, without any of the table-flipping above, the Six-Star reading does both for you. Paste your birth date in. It returns the twelve-type label and the current phase of your cycle, plus a short interpretation tuned to the combination of the two.

For a year-ahead view that uses the same calculation and extends it through the next twelve months, the 2026 preview is the next-most-useful page. Both run on the same math you just read about. You can verify the answer with the tables above if you like. Most people do not. That is what calculators are for.