In Vedic astrology, the Dasha system is very unique in prediction. To predict the timing of the event, knowledge of dasa and bhukti (sub period) is very essential. There are more than 40 types of dasha systems in Vedic astrology. But a very popular and widely accepted dasa system is ‘Vimshottari Dasa System;’. Sage Parashara praised Vimshottari dasa as under:

दशाबहुविधास्तासु मुख्या विंशॊत्तरी मता

which means, amongst all the dashas, Vimshottari is the most appropriate for the general populace. Now there is computer software, which can calculate dasa and antardasa instantly. But it will be good to know the calculation part manually.

Under the Vimshottari Dasha system, the lifespan of a native is considered to be 120 years. This is because in Kaliyuga the normal lifespan of a human being is generally taken as 120 years. And we know that the Vedic astrology considers nine planets (Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu, and Ketu). So 120 years has been divided among these 9 planets to complete one cycle.

The fundamental basis of the Vimshottari dasha system is that it is calculated based on the position of the Moon on different constellations. There are 27 nakshatras or stars in a zodiac of 360° and all the planets will travel along these constellations. So at any point in time, the planets will be posited in one of the 27 nakshatras. The jurisdiction of each nakshatra extends to 13°20’ (or 13*60+20 = 800’). Each nakshatra is divided into 4 parts called padas or quarters and each pada will have 3°20’ of the arc. To calculate the Vimshottari dasa system, the knowledge of Moon’s position is required.

The unique feature of the Vimsottari dasa is that all the planets do not have an equal number of years allotted. There is only one cycle of dasa in 120 years which is divided among 9 planets. Each of the nine planets is assigned 3 nakshatras each. The constellations and years allotted for each planet are given below:

We can see that the years allotted are different for each planet. The sequence of dasha lords should be in the same order from Ketu to Mercury. Each planet is assigned 3 stars assigned to it. At the time of birth, the nakshatra in which the Moon is positioned will become the birth star or Janma Nakshatra. The lord of that star will become the starting dasha for the native. So if the birth star is any of the Ketu’s stars (Aswini, Magha, or Moola), then the starting Dasha will be of Ketu. Thereafter the sequence of dasa of other planets runs. So this is the first step in determining the starting dasha for the native.

When dasha of a particular planet is running, life events are controlled by that planet. For example, when Venus dasha is operating, the events are controlled by Venus for 20 years. Therefore precise timing of events may not be possible and also it would be unfair for the natives if Venus in the birth chart is posited negatively as the native will be troubled for a complete 20 years. To overcome such problems, the dasha periods have been further divided into subgroups. The main dasa period is called ‘Mahadasha’ or ‘Dasha’, which is one cycle with 120 years. The mahadasha is divided into 9 parts and allocated to 9 planets. It is called as ‘Bhukti’ or ‘Antardasha’ or ‘sub period’. Hence under each dasha, 9 bhuktis are allocated. The first Antar Dasa period will always be of the planet whose mahadasha is running and subsequent antardashas will follow the same order of planets as above. Therefore under Venus mahadasha, the first antardasha will be of Venus itself, and then the same order follows. Similarly, it is further divided into subgroups: they are, Pratyantar Dasha, Sookshma Dasha, and Prana Dasha. When we move deeper into sookshma and prana dashas, the span of each period will be in days or even hours.

Calculation of Maha Dasha

Since each nakshatra extends to 13°20’ (800’) of the arc of the zodiac, the number of years allotted will be equated. Hence we need to find out the elapsed longitude of the Moon in a particular star to find out the balance of dasha for the native. Hence equating the full extent of a star (800’) of arc to the full term granted to the lord of the nakshatra, we can work out the balance period equal to the balance of the star yet to be covered by the Moon.

We will understand the concept by taking one example. A native is born on 18 Sep 2014 at 8:30 AM. First, find out the longitude of the Moon in a sign. In this case, Moon is posited with a longitude of 23°56’ in the Gemini sign. The nakshatras or stars belonging to the Gemini sign are Mrigasira, Ardra, and Punarvasu. The first 20 degrees are covered by Mrigasira & Ardra and the remaining 10° will be covered by 3 quarters (padas) of Punarvasu star. Therefore it is understood that the Moon is posited in Punarvasu star. So the first dasha will be of lord of Punarvasu star which is Jupiter. Since the Moon has already covered 3°56’ in Punarvasu star, some dasa period has already elapsed.

Each star will cover 13°20’ or 800’ (13*60+20) of the arc. Moon has already covered 3°56’ (or 3*60+56=236’) in Punarvasu. So the remainder of Punarvasu which is yet to be covered is: 800’-236 = 564’

Therefore, when we convert, 0.28 into days,

Vimshottari dasha balance at birth for Jupiter will be 11 years 3 months 10 days 19 hours 12 Min. or simply 11 years 3 months 11 days

Calculation of Antar Dasha/Bhukti periods

Now we know that all the nine planets have to be fit in the mahadasha period. The antardasha periods also vary according to their mahadasa periods. We also know that the first antardasha will be of the same planet. From the above example, the first antardasha will be of Jupiter under Jupiter mahadasha.

The proportion allotted to Jupiter is 16 years under the mahadasha scheme. Same proportion will be applied to calculate antardashas.

The formula for calculation of dasa period = (Period of the major planet * Sub period of the planet) / 120

In the same manner, Antar dashas for all the lords will be calculated. Note that for the above example, some part of Jupiter dasa has already lapsed at the time of birth. Out of 16 years of Jupiter dasha, 4 yrs and 8 months have elapsed. Therefore Jupiter and Saturn Bhuktis would have been completed. The next antardasha will be of Mercury. Hence the native was having Jupiter mahadasha and Mercury antardasha (or Bhukti) running at the time of birth.

Calculation of Pratyantar Dasha and other sub periods

We need to apply similar formulas to calculate deeper sub-periods.

The formula for Pratyantar dasha ( sub-sub period) = (Period of the major planet * period of sub-planet * Period of the sub-sub planet) / (120 * 120) OR (Period of the major planet * period of sub-planet * Period of the sub-sub planet) / 14400 in months

The formula for Sookshma dasha (sub-sub-sub period) = (Period of major planet * period of antar planet * Period of pratyantar dasa planet * Period of Sookshma dasha planet) / (120 * 120 * 120) in years

The formula for Prana Dasha (sub-sub-sub-sub period) = (Period of major planet * period of antar planet * Period of pratyantar dasa planet * Period of Sookshma dasa planet * Period of Prana dasha planet) / (120 * 120 * 120 * 120) in years