Calculation of Vimshottari Dasha System
In Vedic astrology, 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 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 are computer softwates, which can calculate dasa and antar dasa instantly. But it will be good to know the calculation part manually.
Under Vimshottari dasa system, the lifespan of a native is considered to be 120 years. This is because in Kaliyuga the normal life span 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 Vimshottari dasa system is that it is calculated based on the position of 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 of 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 as padas or quarters and each pada will have 3°20’ of arc. To calculate Vimshottari dasa system, the knowledge of Moon’s position is required.
The unique feature of the Vimsottari dasa is that all the planets does not have 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 are assigned 3 nakshatras each. The constellations and years allotted for each planet is given below:
Planet Constellations Years allotted
Ketu Aswini, Magha and Moola 7 Years
Venus Bharani, PPhalguni and Poorvashadha 20 Years
Sun Krittika, Uttara and Uttarashadha 6 Years
Moon Rohini, Hasta and Shravana 10 Years
Mars Mrigasira, Chitra and Dhanista 7 Years
Rahu Ardra, Swathi and Shathabhisha 18 Years
Jupiter Punarvasu, Vishakha and Poorvashadha 16 Years
Saturn Pushya, Anuradha and Uttarabhadra 19 Years
Mercury Ashlesha, Jyeshta and Revathi 17 Years
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 Moon is posited will become birth star or Janma Nakshatra. The lord of that star will become the starting dasha for the native. So if 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 run. So this is the first step in determining the starting dasha for the native.
When dasha of a particular planet is running, the 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 native if Venus in birth chart is posited negatively as the native will be troubled for 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 of 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. First antardasha 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 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 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 a Gemini sign. The nakshatras or stars belonging to Gemini sign are Mrigasira, Ardra and Punarvasu. First 10 degrees are covered by Mrigasira and Ardra and remaining 10° will be covered by 3 padas of Punarvasu star. Therefore it is understood that Moon is posited in Punarvasu star. So the first dasha will be of lord of Punarvasu star which is Jupiter. Since Moon has already covered 3°56’ in Punarvasu star, some dasa period has already been 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’
Dasha period of Punarvasu with full 800’ whose
lord is Jupiter is = 16 years
Therefore 564’ arc will be = 564*16 / 800
. = 11.28
. = 11 years and 0.28
0.28*12 = 3.36 which means 3 months
0.36*30 = 10.8 which means 10 days
0.8*24 = 19.2 which means 19 hrs
0.2*60 = 12 which means 12 Minutes
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 or Bhukti periods
Now we know that all the nine planets have to be fit in under mahadasha period. The antardasha periods also vary according to their mahadasa periods. We also know that the first antardasha will be of 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 mahadasha scheme. Same proportion will be applied to calculate antardashas.
Formula for calculation of dasa period = (Period of major planet * Sub period of planet) / 120
Therefore Antardasha of Jupiter under
Jupiter dasha will be = (16/120) * 16
. = 2.1333
. = 2 years 1 Month 15 days
Similarly, next Antardasha in the order will be of Saturn = (16/120) * 19
(Note: Saturn is allotted 19 years in 120 years system) = 2.5333
. = 2 years 6 months 12 days
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 been lapsed at the time of birth. Out of 16 years of Jupiter dasha, 4 yrs and 8 months are 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 birth.
Calculation of Pratyantar Dasha and other sub periods
We need to apply similar formulas to calculate deeper sub periods.
Formula for Pratyantar dasha ( sub-sub period) =
(Period of major planet * period of sub planet * Period of sub-sub planet) / (120 * 120)
OR (Period of major planet * period of sub planet * Period of sub-sub planet) / 1200 in months
Formula for Sookshma dasha (sub-sub-sub period) =
(Period of major planet * period of antar planet * Period of pratyantar dasa planet * Period of Sookshma dasa planet) / (120 * 120 * 120) in years
Formula 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