Javanese Weton Calculator

What is weton in the Javanese calendar?

Weton combines two cycles: the familiar 7-day week (Sunday through Saturday) and the 5-day Javanese pasaran cycle — Legi, Pahing, Pon, Wage, and Kliwon — which repeats independently of the 7-day week. Because 7 and 5 have no common factor besides 1, the combination of day and pasaran (for example "Saturday Legi") only repeats every 35 days, a cycle called selapan.

Each day name and each pasaran name carries a traditional numeric value called neptu; adding the day's neptu to the pasaran's neptu gives a person's or a date's total neptu, which is used in traditional Javanese calendar reckoning for choosing dates and matching wetons. This tool computes the day, pasaran and neptu mathematically from the calendar cycle; it does not interpret fortune or compatibility.

How do I find my weton?

To find a weton, take any date, determine its day of the week (Sunday-Saturday) and its position in the 5-day pasaran cycle (Legi, Pahing, Pon, Wage, Kliwon) by counting days from a known reference date, then combine both names. Example: January 1, 2000 falls on Saturday and lands on Legi in the pasaran cycle, so its weton is "Saturday Legi", with neptu 9 (Saturday) + 5 (Legi) = 14.

Steps to calculate a weton

1. Take the target date and find its ordinary day of the week (Sunday through Saturday).
2. Count the number of days between the target date and a known reference date whose pasaran is already established.
3. Take that day-count modulo 5 to find the position in the 5-day pasaran cycle: Legi, Pahing, Pon, Wage, Kliwon.
4. Combine the day name and the pasaran name to get the weton, for example "Saturday Legi".
5. Look up the neptu value for the day and for the pasaran, then add them for the total neptu.

Formula

• Reference date used here: August 17, 1945 (Indonesian Independence Day), documented as Friday Legi
• Day neptu: Sunday 5, Monday 4, Tuesday 3, Wednesday 7, Thursday 8, Friday 6, Saturday 9
• Pasaran neptu: Legi 5, Pahing 9, Pon 7, Wage 4, Kliwon 8

Example weton calculations

Frequently asked questions

What is pasaran and how is it different from the day of the week?

Pasaran is a 5-day market-week cycle unique to the Javanese calendar — Legi, Pahing, Pon, Wage and Kliwon — that runs continuously and independently alongside the familiar 7-day week. Because it has 5 days instead of 7, a given pasaran name lands on a different weekday each time it repeats.

Why does the same weton (day + pasaran) only repeat every 35 days?

Since the 7-day week and the 5-day pasaran cycle run in parallel and 7 and 5 share no common factor other than 1, their combination only realigns to the same pair every 7x5=35 days. This 35-day cycle is called selapan in Javanese tradition.

What does the neptu number mean?

Neptu is a traditional numeric value assigned to each day name and each pasaran name; adding the two gives a person's or a date's total neptu. In Javanese tradition it is used as one input for choosing auspicious dates or comparing wetons, but it is not a scientific or predictive measurement.

Is this tool making fortune-telling predictions?

No. This tool only performs the mathematical calendar calculation — determining the weekday, the pasaran, and the neptu sum from the date you enter. It does not interpret personality, compatibility, or fortune; for traditional ceremonial guidance, consult a primbon reference or a person knowledgeable in Javanese tradition.

This calculator is provided as a cultural and calendrical reference based on a publicly documented historical anchor date and does not constitute fortune-telling, personality assessment, or a guarantee of ceremonial accuracy. For rituals or important traditional decisions, cross-check against a printed primbon or a knowledgeable local source.

Sources: Traditional Javanese calendar (pasaran cycle); reference date: August 17, 1945, widely documented as Friday Legi