In Jain tradition, Panchang is calculated from the five parts of the day:

1. Tithi – lunar date
2. Vaar – weekday
3. Nakshatra – star/constellation
4. Yoga – combination of Sun and Moon positions
5. Karana – half of a tithi

Basic calculation method

To calculate a Panchang, you need the positions of the Sun and Moon for a given date and place.

1. Find the lunar day (Tithi)

• Calculate the angular distance between the Moon and the Sun.
• Divide that distance by 12°.
• The result gives the tithi.
• There are 30 tithis in a lunar month:

- 15 in Shukla Paksha - 15 in Krishna Paksha

2. Find the weekday (Vaar)

• This is simply the day of the week:

- Sunday, Monday, Tuesday, etc.

3. Find the Nakshatra

• Calculate the Moon’s position in the zodiac.
• Divide the 360° circle into 27 nakshatras.
• The nakshatra is based on where the Moon is placed.

4. Find the Yoga

• Add the Sun’s longitude and Moon’s longitude.
• Divide the total by 13°20'.
• The result gives the yoga.

5. Find the Karana

• Each tithi is divided into 2 karanas.
• So one karana covers 6° of the Moon-Sun angular separation.

Practical Jain calendar use

For Jain observances like:

• Paryushan
• Ayambil
• Ekasana
• Pratikraman dates
• Upvas / Tap

people usually follow a verified Panchang prepared by learned Jain scholars or trusted Jain calendar traditions, because correct tithi at sunrise is important.

Very short formula idea

If you have Sun and Moon longitudes:

• Tithi = (Moon − Sun) ÷ 12°
• Nakshatra = Moon longitude ÷ 13°20'
• Yoga = (Sun + Moon) ÷ 13°20'
• Karana = based on half-tithi division

Important note

For exact Jain observances, Panchang is not only about mathematics; it must be checked for:

• Sunrise time
• Local location
• Tithi at sunrise
• Traditional Jain calendar rules

If you want, I can also give you a simple example calculation of Panchang step by step.