What is my Weton? Your Javanese birth day, explained
The Javanese birth day that pairs the seven-day week with the five-day Pasaran cycle — and the Neptu number it carries.
5 min read · Published 29 August 2026
The short answer
Your Weton is your Javanese birth day: the pairing of the ordinary seven-day week with the five-day Pasaran cycle of Legi, Pahing, Pon, Wage and Kliwon. Because the two cycles turn together, a given weekday and a given Pasaran day meet in the same combination only once every 35 days, which is how you get a Weton such as Senin Kliwon. Each Weton also carries a Neptu, a number found by adding the weekday's value to the Pasaran day's value, and that Neptu is what Primbon, the Javanese tradition of reckoning, reads for character, compatibility and timing.
What a Weton is
A Weton is the Javanese way of naming the day you were born. Instead of a single calendar date, it records the day as a *pair* — one name from the familiar seven-day week and one from an older five-day market week called the Pasaran. Put together, they give a Weton like Senin Kliwon or Jumat Legi.
The idea rests on two cycles running side by side. The seven-day week you already know: Minggu, Senin, Selasa, Rabu, Kamis, Jumat, Sabtu. The Pasaran is a separate five-day round — Legi, Pahing, Pon, Wage, Kliwon — that Java has kept alongside the seven-day week for centuries. Every day belongs to both at once.
Because seven and five do not divide evenly, the same combination comes back around only every 35 days (7 × 5). That 35-day round, the *selapan*, is why a Weton feels more specific than a plain weekday, and why Weton birthdays are traditionally marked every 35 days rather than once a year.
The two cycles: week and Pasaran
The five Pasaran days once organised the rotating village markets of Java, each day the market day for a different place. They have long outlived that role and now live on mainly in this reckoning of days.
The five names are worth knowing on their own, because a lot of Javanese day-lore hangs on them:
- Legi — sometimes linked with the east and a sweet or gentle quality.
- Pahing — linked with the south.
- Pon — linked with the west.
- Wage — linked with the north.
- Kliwon — the fifth, often felt as the most charged or central of the five, tied to the middle or the meeting point.
Different regions and different Primbon manuscripts attach slightly different associations to each Pasaran day, so accounts vary. What is constant is the five-name cycle itself and the way it locks together with the seven-day week.
Neptu: the number your Weton carries
Every weekday and every Pasaran day is assigned a small number called a Neptu. Your Weton's Neptu is simply the two values added together. These values are standard and long-established across Primbon, so you can read them straight off the table below.
| Day | Cycle | Neptu value |
|---|---|---|
| Minggu (Sunday) | Week | 5 |
| Senin (Monday) | Week | 4 |
| Selasa (Tuesday) | Week | 3 |
| Rabu (Wednesday) | Week | 7 |
| Kamis (Thursday) | Week | 8 |
| Jumat (Friday) | Week | 6 |
| Sabtu (Saturday) | Week | 9 |
| Legi | Pasaran | 5 |
| Pahing | Pasaran | 9 |
| Pon | Pasaran | 7 |
| Wage | Pasaran | 4 |
| Kliwon | Pasaran | 8 |
A worked example makes it plain. Someone born on Senin Kliwon — Monday Kliwon — takes Senin at 4 and Kliwon at 8, so their Neptu is 4 + 8 = 12. Someone born on Jumat Legi takes 6 + 5 = 11. That single number is the raw material Primbon then works with.
What Weton is used for
Once you have the Weton and its Neptu, the tradition reads them in several directions. Character and temperament are drawn from the day itself. Timing is another use: choosing an auspicious day for a wedding, a move, or the start of something is often done by weighing Wetons and Neptu against one another.
Compatibility is one of the best-known uses of all. Two people's Neptu can be added and read for how well-matched they are said to be — the subject of our companion piece, are our Wetons compatible?. All of this belongs to Primbon, the broad Javanese body of divinatory and calendrical knowledge; if the word is new to you, start with what is Primbon?.
None of it is treated as fixed fate even within the tradition. A Weton is read as a tendency and a guide, one input among many, rather than a sentence handed down at birth.
Finding your own Weton
Working a Weton out by hand means converting your birth date across the Javanese calendar to land on the right weekday and the right Pasaran day at once — fiddly to do from scratch, and easy to get wrong by a day. The AsterNym Weton calculator does the conversion for you and returns your full Weton and its Neptu from your birth date.
From there the rest of this cluster opens up: the compatibility reading, and the wider world of Primbon behind both.
Common questions
- What is a Weton?
- A Weton is your Javanese birth day, recorded as a pair: one name from the seven-day week and one from the five-day Pasaran cycle of Legi, Pahing, Pon, Wage and Kliwon. An example is Senin Kliwon, meaning Monday Kliwon.
- How is Neptu calculated?
- Neptu is a number found by adding the weekday's standard value to the Pasaran day's value. For example, Senin (Monday) is 4 and Kliwon is 8, so a Senin Kliwon Weton has a Neptu of 12. The weekday and Pasaran values are fixed and long-established in Primbon.
- Why does a Weton repeat every 35 days?
- Because the seven-day week and the five-day Pasaran cycle run at the same time, and seven multiplied by five is thirty-five. Any particular combination of weekday and Pasaran day therefore comes back around only once in every 35-day round, called the selapan.
- What is a Weton used for?
- In Javanese tradition a Weton and its Neptu are read for character and temperament, for choosing auspicious dates for events such as weddings, and for judging compatibility between two people. It is treated as a guide and a tendency rather than as fixed fate.