Calcul Kua Gua
Use this premium calculator to estimate your traditional Kua number from your date of birth and gender convention used in the Eight Mansions method. The tool can apply the common Li Chun cutoff on February 4, then show your group, element, and favorable compass directions.
Expert Guide: How calcul kua gua works and how to use it well
The phrase calcul kua gua usually refers to calculating a personal Kua number, sometimes also called a Gua number, in the Eight Mansions branch of feng shui. The purpose of this number is simple: it classifies a person into an East group or West group, then links that group to a set of supportive and less supportive directions. In practice, people use the result when thinking about the direction of a desk, the orientation of a bed, a personal meditation space, or the facing direction used during work or study.
Even though the method is traditional and symbolic rather than scientific, many people want a calculator because the manual process is easy to get wrong. There are several reasons for that. First, the formula is different for births before 2000 and births from 2000 onward. Second, the traditional year boundary often follows Li Chun, the start of spring, rather than January 1. Third, the number 5 is not usually kept as a final personal Kua number in this system: it is converted to 2 for the male formula and 8 for the female formula. A good calculator handles all three issues cleanly.
What the Kua number tells you
Your Kua number maps to one of two major groups:
- East group: Kua 1, 3, 4, 9
- West group: Kua 2, 6, 7, 8
Each number is also associated with a trigram, an element, and four favorable plus four less favorable directions. Many practitioners use the favorable set for personal positioning, such as where to face while working, reading, praying, or sleeping. The less favorable set is often treated as secondary or neutralized through layout changes rather than feared. In other words, the Kua number is meant to guide placement choices, not to dominate every decision in a house or office.
The basic formula behind calcul kua gua
The traditional method starts with the year of birth, but not always the Gregorian year you see on your birth certificate for January and early February birthdays. If you use the Li Chun convention, a person born before February 4 belongs to the previous energetic year. That is why many calculators ask for the exact birth date, not only the birth year.
Once the correct year is chosen, the last two digits are reduced to a single digit. Then the gender rule is applied:
| Birth period | Male formula | Female formula | Important adjustment |
|---|---|---|---|
| 1900 to 1999 | 10 minus reduced year digit | 5 plus reduced year digit, then reduce again | If final result is 5, convert to 2 for male and 8 for female |
| 2000 onward | 9 minus reduced year digit | 6 plus reduced year digit, then reduce again | If final result is 5, convert to 2 for male and 8 for female |
Example: suppose someone was born on March 12, 1991 and uses the male formula. The last two digits are 91. Add 9 + 1 = 10, then reduce 1 + 0 = 1. Since 1991 is before 2000, calculate 10 minus 1 = 9. The Kua number is 9. If the same birth date used the female formula, the result would be 5 + 1 = 6, so Kua 6.
Now take a more sensitive example: February 2, 2001. If you follow the Li Chun convention, the energetic year is still treated as 2000, because the birth date is before February 4. That changes the formula and can change the final Kua number. This is the single most common source of confusion in online calculations, so it is smart to compare both methods when your birthday sits near the cutoff.
Why Li Chun matters
Li Chun is one of the 24 solar terms in the traditional East Asian solar calendar. In many feng shui schools, the annual energy used for Kua calculations begins at Li Chun, usually around February 4. If you want a reliable calendar reference, the Hong Kong Observatory provides official explanatory material on date conversion and calendar systems. For broader historical context on traditional calendar structure, Columbia University also offers useful educational material on the Chinese calendar.
From a practical standpoint, Li Chun matters because feng shui formulas are trying to map a person into a symbolic energy cycle rather than a civil or tax year. Whether you accept that framework literally or simply use it as a traditional planning tool, the logic of the system becomes more consistent when the same seasonal boundary is used each time.
How compass directions are divided
When your Kua number gives you favorable directions, you still need to understand what a direction means in degrees. A direction is not just a vague label. It usually refers to a compass sector, and each of the eight main sectors spans 45 degrees. This is one reason why compass quality matters. If you are using a phone, local magnetic interference from metal furniture, speakers, appliances, or reinforced concrete can affect readings. For practical orientation guidance and declination tools, NOAA provides authoritative navigation resources through its magnetic declination calculator.
| Direction | Center bearing | Typical degree span | Use in Kua interpretation |
|---|---|---|---|
| North | 0 degrees | 337.5 degrees to 22.5 degrees | Commonly used for facing, sleeping, or desk orientation |
| Northeast | 45 degrees | 22.5 degrees to 67.5 degrees | Important for West group Kua numbers 2, 6, 7, 8 |
| East | 90 degrees | 67.5 degrees to 112.5 degrees | Important for East group Kua numbers 1, 3, 4, 9 |
| Southeast | 135 degrees | 112.5 degrees to 157.5 degrees | Frequently appears among favorable sectors for East group users |
| South | 180 degrees | 157.5 degrees to 202.5 degrees | Often used in facing direction choices |
| Southwest | 225 degrees | 202.5 degrees to 247.5 degrees | Frequently appears among favorable sectors for West group users |
| West | 270 degrees | 247.5 degrees to 292.5 degrees | Common favorable sector in several West group charts |
| Northwest | 315 degrees | 292.5 degrees to 337.5 degrees | Often linked with supportive positioning for West group users |
Using your result in real life
Once you know your Kua number, use it as a prioritization tool. Start with the places where your body spends the most time or where concentration matters most. For most people, that means a bed, a work chair, or a study desk. If your favorable directions are East, Southeast, South, and North, try first to face one of those directions when doing deep work. If you cannot change your desk, you might adjust your chair angle or use the more favorable direction for a secondary activity such as reading or video calls.
Bedrooms are often treated differently depending on the school. Some practitioners emphasize the direction your head points while sleeping, while others focus more on the room sector or the bed placement relative to the door. If you want to use Kua in a calm and balanced way, avoid trying to optimize every variable at once. Pick one or two meaningful changes, test how the room feels, and keep what is practical.
Common mistakes people make
- Using the wrong year boundary. People born near February 4 are the most likely to receive a different Kua number under Li Chun versus January 1 methods.
- Reducing the wrong digits. Most traditional formulas use the last two digits of the effective birth year, then reduce them to a single digit.
- Forgetting the post-2000 rule. The formulas change after 1999.
- Leaving 5 as the final result. In this method, 5 is typically converted to 2 for male and 8 for female.
- Confusing facing direction with room direction. Personal Kua advice usually applies to the direction you face or orient yourself toward, not automatically to the legal address orientation of the whole building.
- Ignoring compass interference. A phone compass can swing if you stand near metal shelving, electronics, or structural steel.
What this calculator is best for
This calculator is most useful when you want a fast and consistent answer to the foundational question: what is my Kua number under a common traditional formula? It is especially valuable if you are comparing two possibilities around the February cutoff or if you want an immediate visual of favorable versus unfavorable directions. The included chart helps turn abstract direction lists into something easier to read at a glance.
It is not meant to replace a full feng shui consultation. Professional practice may incorporate additional layers such as house period, door facing, form school observations, room shapes, external environment, and detailed compass methods. Still, for many users, personal Kua is the simplest and most approachable starting point.
Frequently asked questions
Is Kua the same as astrology? Not exactly. It overlaps with traditional cosmology, but the Kua number in this context is primarily a directional classification tool.
Can two calculators give different answers? Yes. The most common reasons are different year boundaries, different handling of edge dates, or a calculator that applies an incorrect post-2000 formula.
What if my favorable direction is impossible in my room? Use the best feasible alternative. Most practitioners recommend practicality first. A comfortable, safe, and uncluttered room usually matters more than forcing an exact compass angle.
Should I trust a phone compass? It is good for a first pass, but recalibrate the device and check readings from more than one location in the room. If you need precision, compare with a dedicated compass and remember that local magnetic conditions can affect the result.
A balanced final takeaway
Calcul kua gua is easy to learn but easy to miscalculate. The strongest approach is methodical: choose your year boundary, use the correct pre-2000 or post-2000 formula, reduce carefully, and apply the traditional conversion if the result lands on 5. Then use the number as a gentle planning tool for orientation, not as a rigid rule that overrides comfort or common sense.
When used this way, a Kua calculator becomes genuinely practical. It saves time, reduces arithmetic mistakes, clarifies favorable directions, and gives you a repeatable method for personal positioning. If your birthday is close to early February, compare both methods, note which convention your preferred school follows, and keep your interpretation consistent from one project to the next.