What is an ishta devata in Jyotish?
The ishta devata (इष्ट देवता, the cherished deity) is the form of the divine a person is drawn to worship by choice, as distinct from the family deity inherited with the lineage. Jaimini's system reads it from the chart through the karakamsha, the navamsa sign the Atmakaraka occupies, because the Atmakaraka is the significator of the self and the 12th is the house of release and surrender. The reading names a graha, and the graha is mapped to a deity by a table the tradition has carried in more than one form. It is a pointer for devotion that the texts offer, not a ranking of deities and not a statement about anyone's faith.
Ishta, kula and palana devata are three different ideas
The kula devata is the family or clan deity, known from the family rather than from a chart. The ishta devata is the personal chosen deity, read here from the 12th from the karakamsha. The palana devata, the sustaining deity, is a later convention read from the 6th. They can coincide and often do not, and none of them replaces the others in the practice that uses all three.
A pointer for devotion, not a verdict on belief
The texts use the karakamsha to say which form of worship suits the self the Atmakaraka stands for. That is a traditional reading, offered as a starting point. It does not say any other deity is wrong for a person, and nothing about it has been shown to change anything in anyone's life. The result on this page is written in that spirit: the association and its variants, with the working.
How does the ishta devata calculator work by date of birth?
It runs four steps, and the result prints each one. First the Atmakaraka: the graha furthest advanced within its own sign, with Rahu counted backwards and Ketu excluded. Second the karakamsha: the navamsa (D9) sign that Atmakaraka falls in. Third the 12th sign from the karakamsha, counting the karakamsha itself as the 1st. Fourth the indicator: any graha occupying that sign in the navamsa, or, if it is empty, the sign's lord. The indicator is then looked up in the deity table. Because the D9 needs degrees, the date of birth is only half the input; the time and place fix the positions the whole chain depends on.
Step one: which graha is the Atmakaraka
Each graha's degrees within its sign are ranked from highest to lowest. Rahu's are measured as 30° minus its degrees, because it moves retrograde, and Ketu takes no chara karaka at all. The top of the ranking is the Atmakaraka. The full ranking, with both karaka schemes, is set out on the atmakaraka calculator, and this page applies the same ranking rule to reach it.
Step two: the karakamsha and the sign twelve from it
The navamsa cuts each sign into nine parts of 3°20'. Movable signs start the count from themselves, fixed signs from the 9th, dual signs from the 5th. Wherever the Atmakaraka lands is the karakamsha. The result then draws the whole navamsa turned so the karakamsha sits in the first house, which makes the 12th house of that drawing the sign being read.
Who is my ishta devata, graha by graha?
The association commonly cited from the Jaimini Sutras and later commentary runs: Sun, Shiva (Surya in some lists); Moon, Parvati or Gauri; Mars, Skanda, with Hanuman in much north Indian practice; Mercury, Vishnu; Jupiter, Shiva as Dakshinamurti in one tradition and Vishnu in another; Venus, Lakshmi; Saturn, Vishnu or Narayana, with some writers reading Shani; Rahu, Durga; Ketu, Ganesha. The result names the first form and prints the alternates beside it, because the lists genuinely vary and choosing one silently would hide that.
The BPHS avatara list is a separate table
Brihat Parashara Hora Shastra, in its second chapter, attaches an avatara of Vishnu to each graha: Rama to the Sun, Krishna to the Moon, Narasimha to Mars, Buddha to Mercury, Vamana to Jupiter, Parashurama to Venus, Kurma to Saturn, Varaha to Rahu and Matsya to Ketu. It is a different list made for a different purpose, so the result shows it in its own line rather than mixing it into the ishta devata table.
When two grahas share the 12th
If more than one graha occupies the sign, each is an indicator and each deity is listed. Commentators who want a single answer take the stronger graha, and there is no one agreed measure of strength for this purpose, so the page lists them all rather than picking one by a rule it would have to invent. The lord of the sign is printed too.
Why the 12th from the karakamsha, and where do commentators differ?
The 12th is the house of loss, expenditure and final release, and read from the self's own significator it becomes the place the self lets go into something larger. That is the reasoning the tradition gives for reading the chosen deity there. Beyond it, three points are genuinely contested. Some writers read the lord of the 12th even when a graha occupies it; others take the stronger of occupant and lord. Some use the seven-karaka scheme, which leaves Rahu out and can name a different Atmakaraka. And the deity table itself varies. This page applies occupant first, else lord, and shows the alternatives on every one of the three.
Occupant first, and the lord shown anyway
The rule applied is the plainest reading of the sutra and the one most later commentators state: a graha in the 12th from the karakamsha speaks first, and an empty sign is read through its lord. Where the sign is occupied, the result still names the lord and its deity in a separate line, so a reader who follows the lord-only school has the answer that school would give.
Seven karakas or eight changes the starting point
If Rahu is the furthest-advanced graha when counted backwards, the eight-karaka scheme makes it the Atmakaraka and the seven-karaka scheme does not. The karakamsha then differs, and so does everything counted from it. The result checks both schemes and prints the seven-karaka reading in full whenever it disagrees.
Can I use an ishta devata calculator without birth time?
Not reliably, and the reason is the navamsa. Each navamsa is 3°20', so the Moon crosses one in roughly six hours, and even the slower grahas can sit close enough to an edge that a day's uncertainty moves them. The Atmakaraka itself can change within a day when the Moon is near the top of the ranking. A page that gave an ishta devata from the date alone would be guessing at the karakamsha and presenting the guess as a reading. With an approximate time, the result tells you how far the Atmakaraka sits from the edge of its navamsa, which says how much error the answer can absorb.
What is the palana devata, and is it the same reading?
The palana devata, the sustaining or guardian deity, is read from the 6th sign from the karakamsha in the navamsa by the same occupant-else-lord rule. It is a later convention taught in modern Jaimini schools rather than a rule stated in the sutras, and some teachers count it from the Amatyakaraka instead of the Atmakaraka. The result prints it, labelled as that convention, because it is widely asked about. The ishta devata is the reading this page is built around; the palana devata is shown beside it, not in place of it, and the two can point to the same deity or to different ones.
Is this a free ishta devata calculator, and what does it need?
Yes, it is free and online, with no sign-up. It needs the date, the time and the place of birth: the place fixes the time zone and the local time converts to the moment the positions are calculated for. Longitudes are sidereal on the Lahiri (Chitrapaksha) ayanamsha with the mean node, the kundli page's default settings, so the Atmakaraka here matches the karaka table in your kundli. If another ishta devata calculator online gives a different deity, the usual reasons are a different ayanamsha, Rahu ranked forwards, the lord read instead of the occupant, or a different deity table.
How this is calculated
Nirayana rashis with the Lahiri (Chitrapaksha) ayanamsha and whole-sign bhavas, computed to arc-second accuracy. Sunrise and sunset are the ones almanacs show, the Sun's upper edge with refraction, so the daily windows agree with the calendars you compare them with. More on our method.