AstroLogics API

AstroLogics team ·

How the Vimshottari dasha is calculated

The Vimshottari dasha divides a life into periods ruled by the nine grahas. This post works through one made-up birth: 13 August 1990 at 06:30 in New Delhi.

The cycle

The nine lords always come in the same order, and their years add up to 120:

Lord Ketu Venus Sun Moon Mars Rahu Jupiter Saturn Mercury
Years 7 20 6 10 7 18 16 19 17

Each of the 27 nakshatras has one of these lords, in the same order from Ashwini (Ketu), Bharani (Venus) and Krittika (Sun) onwards.

The balance at birth

The first period is the lord of the Moon's nakshatra, and only the part the Moon has not yet crossed is left.

  1. The Moon is at 18.0955° in Aries. That is in Bharani, which runs from 13°20′ to 26°40′, so the lord is Venus.
  2. The Moon has crossed 4.762° of Bharani's 13.333°, which is 35.72%.
  3. So 64.28% of Venus's 20 years is left: 12.857 years.

The balance starts at birth and ends on 21 June 2003. From there each lord runs its full term: the Sun to June 2009, the Moon to June 2019, and so on. The API returns these inputs in data.basis, so you can check the arithmetic yourself.

How long a year is, is a convention. We use 365.25 days by default, and options.dasha_year takes other lengths.

Sub-periods

Each mahadasha divides into nine antardashas, in the same order, starting with its own lord. Each lasts the mahadasha's years times its lord's years, divided by 120. The Sun's 6 years start with the Sun's own antardasha of 6 × 6 / 120 = 0.3 years.

The first mahadasha needs care, because it was already running at birth. Venus's full 20 years would have started 7.14 years before birth. Its antardashas over those 7.14 years were Venus (3.33 years), the Sun (1), the Moon (1.67) and most of Mars (1.17). So this birth falls in the last eight days of Venus-Mars:

Antardasha From To
Mars birth 21 August 1990
Rahu 21 August 1990 21 August 1993
Jupiter 21 August 1993 21 April 1996
Saturn 21 April 1996 21 June 1999
Mercury 21 June 1999 21 April 2002
Ketu 21 April 2002 21 June 2003

The levels below work the same way: pratyantardasha, sookshma and prana.

Until engine 2026.10.10 our API got this part wrong. It squeezed all nine antardashas into the 12.86 years left, starting with Venus's own. The changelog records the fix.

In the API

curl -X POST 'https://api.astrologics.in/v1/dasha/vimshottari' \
  -H 'Authorization: Bearer al_test_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"birth":{"date":"1990-08-13","time":"06:30","place":{"latitude":28.6139,"longitude":77.209}},"depth":2}'

Send depth from 1 to 5 for the levels you need. For only what is running at a moment, use POST /v1/dasha/vimshottari/current (2 credits).

The calculation depends on the Moon to a fraction of a degree. An error of four minutes in the birth time moves the Moon about 2′. In Bharani that is 2 of its 800 arcminutes, so every dasha date moves by about 20 days. So the timezone matters too.

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