Thai Birth Day Calculator
Enter the local date from your birth record, and your birth time too if you know it.
How the birth-weekday calculator works
How a birth date becomes a weekday
Thai astrology starts from one question: which weekday were you born on? So the first thing this calculator does is find the weekday of the solar (Gregorian) birth date you enter. It is plain calendar arithmetic, so anyone who does it gets the same answer. For example, May 15, 2000 was a Monday. This site accepts dates from 1900 up to today.
There is a tradition in Thailand of treating the day as beginning at dawn rather than at midnight. To keep the calculation transparent, this site fixes 6:00 a.m. as the boundary between days. So someone born at 5:30 a.m. on a Monday is counted as Sunday, while someone born at 3:00 p.m. that same Monday is counted as Monday. The actual time of sunrise is not used. Some astrologers do go by sunrise, so the same person can be read slightly differently from book to book, and we say so openly.
Wednesday alone is split into day and night. From 6:00 a.m. until just before 6:00 p.m. on Wednesday is “Wednesday daytime,” ruled by Mercury; from 6:00 p.m. until 5:59 a.m. the next morning is “Wednesday night,” ruled by Rahu. That is why there are seven weekdays but eight results. For example, March 12, 2003 was a Wednesday: born at 2:00 p.m. means Wednesday daytime, and born at 9:00 p.m. means Wednesday night. Born at 2:00 a.m. that same date counts as the Tuesday before. And a birth at 2:00 a.m. on March 13, in the early hours of Thursday, still belongs to the previous Wednesday night.
If you do not know the birth time, we show the candidates
Not knowing your birth time does not mean we quietly pick one for you. We show every category that is possible within that day. For a Monday, the hours before and after 6:00 a.m. give Sunday or Monday; for a Wednesday, there are three possibilities: Tuesday, Wednesday daytime, and Wednesday night. We do not tell you which is most likely as a probability. Turning “I don’t know the time” into a number would only create a false sense of precision.
If you can find the time from your parents, a birth record, or a family album, try entering it again. Changing even a single field can change the resulting weekday. And if you truly cannot find it, you can read the stories for each candidate side by side and save the one that speaks to you.
What you get from the result
Once the weekday is set, you see that weekday’s traditional details in one place: the Thai name of the day, your birth year in the Buddhist Era (พ.ศ., the Gregorian year plus 543), the planet that rules the day and its guardian animal, the day’s Buddha image, and the day’s color. Then the eight planets are laid out in order on a diagram of eight seats called the taksa (ทักษา), showing which planet and color sit in seats such as The People Around Me, Life Force, Influence, and Fortune.
The result does not declare “you are this kind of person.” It is a self-exploration story built on symbols that Thai people have talked about for a long time, meant to be read together with questions you can ask yourself. It is more fun to notice which sentence your mind lingers on than to decide whether it is right or wrong.
How to read your result
In Thailand it is not unusual to ask someone you have just met, “What day were you born?” (เกิดวันอะไร). Knowing a person’s weekday before their name is part of the culture, and the weekday can serve as a one-line introduction. Try approaching your result in the same light way. Pick just one thing you like among the day name, the guardian animal, and the color, and write down, “If this were a one-line introduction of me, what would the sentence be?”
The taksa diagram shows all eight seats at once, so it can look like a lot at first. Start by reading the Fortune seat and The People Around Me, and look at the rest slowly; that keeps it light. Whichever seat overlaps with your life right now, use it as material for a conversation or a note.
Where does your birth date go?
In the free calculation, the birth date and time you enter are worked out only inside the browser you have open. They are not sent to a server, and they are not left in the address, in share cards, or in browser storage. When you refresh or leave the page, what you entered is gone. The links and cards you share with friends carry only which weekday category it is, never a birth date. If you want to keep a result for later, it is saved to this device only when you press “Save” yourself.
Frequently asked questions about the calculator
I only know my lunar birthday. How do I enter it?
This calculator accepts solar (Gregorian) dates only. If you know your birthday in a lunar or lunisolar calendar, convert it to a Gregorian date first and then enter that. Converters are easy to find through calendar apps or public observatory sites for the calendar you use. For a leap month, be sure to pick the leap-month option in the converter so the result is accurate.
I was born abroad. Do I need to convert to my home time zone?
No. Enter the local date and local time of the place where you were born, exactly as they were. The calculator does not convert time zones; it goes by what the calendar and clock showed at your birthplace.
I was born at 3:00 a.m. Which weekday will I get?
Anything before 6:00 a.m. is counted as the previous day. For example, a birth at 3:00 a.m. on a Monday comes out as Sunday. The same goes for births just after midnight. This turns the tradition into a simple rule, so the result may differ from other books that go by sunrise.
How do I use the Buddhist Era (พ.ศ.) year?
In the current official Thai calendar, you get the Buddhist Era year by adding 543 to the Gregorian year. The year 2000 is 2543. This calculator takes only Gregorian years, and it does not guess and convert a Buddhist Era number into a Gregorian one. The result screen shows how your birth year is written in the Buddhist Era.
The result seems wrong. What should I check?
First, check that the date is solar rather than lunar and that the year, month, and day are in the right order. Next, see whether your time falls close to 6:00 a.m., or for Wednesday, close to 6:00 p.m. Near these boundaries the result can differ by a day. If it still looks different, it may simply be the gap between books that use sunrise and this site, which uses fixed times.
Can I see a result if I do not know my birth time?
Yes. If you leave the time blank, we show every weekday category that is possible. Wednesday gives three candidates and the other days give two. Instead of pinning down exactly which is right, you can read each candidate in turn and find the story that speaks to you.
Does it work for dates before 1900 or after today?
This free calculator supports Gregorian dates from 1900 up to today. Outside that range you will see a message asking you to check the date. If the supported range ever changes, we will update this explanation along with it.