Vimshottari Dasha

What this page adds to the calculator above

The calculator above gives you three things: nine dated Mahadashas, the one running today, and its nine Antardashas. The notes beside it state the method in two paragraphs. This long-form goes further in four directions: where the system is written down in the classical literature, the arithmetic line by line with a real engine run you can check by hand, what the tradition says a period means and how this app applies that test, and exactly how much a wrong or missing birth time moves the dates. If you want the short conceptual introduction first, read what a Mahadasha is and come back.

Where Vimshottari comes from

The primary source is the Brihat Parashara Hora Shastra (BPHS), Chapter 46, titled Dashas of Grahas. The chapter opens with Maitreya asking Parashara about the different kinds of planetary periods. The answer in slokas 2-5 is the sentence every later book leans on: dashas are of many kinds, and among them Vimshottari is the most appropriate for the general populace. The same passage then lists nine others followed in special cases - Ashtottari, Shodshottari, Dwadashottari, Panchottari, Shatabdik, Chaturashiti-sama, Dwisaptati-sama, Shastihayani and Shat-trimshat-sama - and says all of them are based on nakshatras.

Slokas 12-14 give the rule itself. Beginning from Krittika, the lords of the dashas are Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury, Ketu and Venus, in that order. Count the nakshatras from Krittika to the birth nakshatra, divide by nine, and the remainder names the lord of the dasha running at birth. The others follow in the same order. The text also gives its reason for the name: the natural span of human life in Kali Yuga is generally taken as 120 years, and Vimshottari means one hundred and twenty. Sloka 15 gives the lengths: 6, 10, 7, 18, 16, 19, 17, 7 and 20 years for the nine lords in that order. They add to 120.

Sloka 16 gives the last ingredient, the balance at birth. Multiply the dasha length of the lord concerned by the time the Moon has already spent in the birth nakshatra, and divide by the total time the Moon spends in that nakshatra. That is the expired part of the dasha. Subtract it from the full length and what remains is the balance of dasha at the moment of birth. Everything on this page is those three slokas turned into dates.

A much later book in this app's source shelf, the modern case-study compilation Advanced Predictive Astrology, calls the same system Udu Dasa and describes it as the most popular of the dasha systems and the one that has stood the test of time. That is the author's judgement, not a measurement, and it is reported here as such. What can be said without qualification is that BPHS itself ranks Vimshottari first for general use, and that is why it is this app's main dasha display.

The nine lords, their years and their nakshatras

Each lord owns three of the 27 nakshatras, spaced nine apart. The engine stores the sequence starting from Ketu because it counts nakshatras from Ashwini, the first one; BPHS states it starting from the Sun because it counts from Krittika, the third. It is the same circle read from two different starting points, and both give the same lord for every nakshatra. You can confirm your own birth nakshatra and its lord on the Nakshatra calculator.

How the engine computes it, step by step

1. 1.The Moon's sidereal longitude is computed for the birth instant, with the Lahiri ayanamsa subtracted from the tropical position. The value of that offset for any date is on the Ayanamsa calculator, and the astronomy behind the Moon's position is described on the methodology page.
2. 2.The longitude is divided by 13 degrees 20 minutes (360 divided by 27). The whole part is the nakshatra index, 0 for Ashwini to 26 for Revati. The remainder, divided by 13 degrees 20 minutes again, is the fraction of the nakshatra the Moon has already crossed, a number from 0 to 1.
3. 3.The nakshatra index modulo nine picks the opening lord from the stored sequence Ketu, Venus, Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury.
4. 4.The first period is given the opening lord's full years multiplied by one minus the elapsed fraction. It starts at the birth instant and is flagged as partial.
5. 5.The remaining eight lords follow in sequence at full length. Years are converted to time at 365.2425 days per year, and each period starts on the instant the previous one ended.
6. 6.The running Mahadasha is the period whose start is at or before the present moment and whose end is after it.
7. 7.That period's span is shared among nine Antardashas in proportion to each lord's years out of 120, beginning with the Mahadasha's own lord and continuing in the fixed order.

The ascendant plays no part in any of these steps. That is why the calculator asks only for a birth date and treats the time as optional: the single input the arithmetic reads is where the Moon was. A place is not needed for the same reason. When no time is given, the chart is cast at noon on the birth date, on Indian Standard Time when no place fixes a zone, and the result is marked as having an assumed time.

Every Antardasha length, in months

Because the rule is a product of two year-lengths divided by 120, the length of any full Antardasha in months is simply the two lords' years multiplied together and divided by ten. The table is therefore symmetric: Saturn inside Venus is as long as Venus inside Saturn. A month here means one twelfth of the engine's 365.2425-day year.

The shortest sub-period in the whole system is the Sun inside the Sun, 3.6 months. The longest is Venus inside Venus, 40 months, which is longer than three years. So the common statement that someone is in a particular Mahadasha and Antardasha can describe a window of a few months or one of several years, depending on which pair it is.

A worked example you can check by hand

The sample on this page uses a birth date of 14 August 1994 with no time. Run through the real engine, the chart cast at noon IST puts the Moon at sidereal longitude 207.7575 degrees. Here is every step from that one number to the dates.

1. 1.207.7575 divided by 13.3333 is 15.58. The whole part, 15, is the sixteenth nakshatra counting Ashwini as the first: Vishakha, which runs from 200 degrees to 213 degrees 20 minutes. In signs, 207.7575 is 27.76 degrees of Libra.
2. 2.15 modulo 9 is 6, and the lord at position 6 of the stored sequence (counting Ketu as 0) is Jupiter. The BPHS count gives the same answer by its own route: Krittika to Vishakha is fourteen nakshatras, fourteen divided by nine leaves five, and the fifth lord in the order Sun, Moon, Mars, Rahu, Jupiter is Jupiter.
3. 3.The Moon is 7.7575 degrees into Vishakha. Divided by 13.3333 that is 0.58181, so 58.18 per cent of Jupiter's period is treated as already spent.
4. 4.The balance is 16 years multiplied by 0.41819, which is 6.6911 years. Added to the birth instant at 365.2425 days a year, the Jupiter period ends on 23 April 2001.
5. 5.Saturn's full 19 years run from there to 22 April 2020, and Mercury's 17 years to 22 April 2037.

The nine rows cover 110.69 years, not 120, because the first 9.31 years of the Jupiter period fall before the birth. That is the general pattern: the timeline always spans 120 years minus whatever part of the opening period had already run.

The Antardashas inside the running period

Mercury's Mahadasha is 17 years, so each Antardasha is 17 times its own lord's years divided by 120. The engine's dates and day counts for this chart are below.

The nine lengths add to 6,209.1 days, which is 17 years at 365.2425 days, so the parts sum to the whole. BPHS Ch. 51 Sl. 1 and Ch. 61 Sl. 1 carry the same rule one level further down, to the Pratyantardasha: multiply the Antardasha's length by each lord's years and divide by 120. This calculator stops at two levels, but the engine has the third as its own function, and running it on the Sun Antardasha above gives nine pieces of 15.5, 25.9, 18.1, 46.6, 41.4, 49.2, 44.0, 18.1 and 51.7 days, for Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury, Ketu and Venus. On 6 October 2026 the third-level lord for this chart is Rahu, from 14 September to 31 October 2026. The reasoning behind the lower levels is set out in Antardasha and Pratyantar explained.

How to read each part of the result

The timeline

Nine rows, each with a lord, that lord's full years, a start and an end. The first row carries a partial flag; its dated length is shorter than its full years by the fraction the Moon had already crossed. The full-years figure on that row is the lord's standard length, not the time you actually spend in it. To see the length you spend, read the dates.

The Antardashas

Nine rows, each with a lord, a start and an end, all nested inside the current Mahadasha. The first always has the same lord as the Mahadasha itself, as BPHS Ch. 51 Sl. 2 requires. The calculator does not mark which of the nine is running; compare the dates with today to find it.

What the classical texts say a period means

The calculator dates the periods and stops. It does not say whether a period is good or difficult, and it could not do so honestly from a birth date alone, because the classical test needs the houses. It is still worth knowing what that test is, since it is what the signed-in parts of the app apply.

BPHS Ch. 47 Sl. 2 separates two kinds of dasha effect. General effects come from the natural character of the graha. Distinctive effects come from its placement in the particular chart. Slokas 5-6 then give the placement test in one sentence each way. The effects are favourable if, at the commencement of the dasha, the dasha lord is in the Lagna, in its exaltation sign, in its own sign, or in a friendly sign. They are unfavourable if the lord is in the sixth, eighth or twelfth house, in its debilitation sign, or in an enemy's sign.

This app's engine applies that test literally. For the lord of the running period it reads the lord's dignity and house from your chart and calls the period favourable only when the lord is exalted, in Moolatrikona, in its own sign or a friendly sign, or stands in the Lagna - and is not debilitated, not in an enemy sign, and not in the sixth, eighth or twelfth. Anything else is labelled testing, and the sentence it prints says the period is classically read that way, which marks the claim as the tradition's and not as a forecast. Because it needs the ascendant, that reading appears in the signed-in Kundali and is not part of this public calculator. You can see the dignity side of the test for all nine grahas on the Shad Bala calculator, and the ascendant itself on the Lagna calculator.

When inside the period the effects are said to show

BPHS Ch. 47 Sl. 3-4 adds a timing refinement that is easy to overlook. The effects of a graha in the first Dreshkana, the first ten degrees of its sign, are said to be realised at the commencement of its dasha; those of a graha in the second Dreshkana in the middle; those of a graha in the third at the end. For a retrograde graha the order is reversed, and since Rahu and Ketu are always retrograde, their effects are always read in the reverse order. The text also says the effects are in accordance with the graha's strength. This app does not apply the Dreshkana refinement anywhere; it is reported here as what the source says.

The conditions BPHS gives for each lord

The rest of Chapter 47 goes through the nine lords one at a time. The results it lists are in the idiom of a royal court - kingdoms, conveyances, elephants, honours from the sovereign - and are best read as a vocabulary for gain and standing, not as a list of things to expect. The conditions are the useful part, and they are consistent from lord to lord.

Each lord also has its own longer page in the learn section: Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury, Ketu and Venus Mahadasha.

The lord as owner of houses

Chapter 48 of BPHS adds a second layer: the same graha is also the lord of one or two houses in your chart, and its dasha takes colour from them. Sloka 1 states the principle that settles most apparent contradictions - a natural malefic in its exaltation sign and in an auspicious house does not produce unfavourable results, and a natural benefic that is debilitated and in an inauspicious house does. Slokas 14-17 give exceptions in the other direction: the dasha of a sixth, eighth or twelfth lord becomes favourable if that lord is associated with the lord of a Trikona, and the dasha of a graha aspected by a Kendra or Trikona lord is favourable. The chapter closes its main list with an instruction about method: the placement of a graha at birth and at the commencement of its dasha should both be taken into account.

For sub-periods, BPHS gives nine whole chapters, 52 to 60, one for each Mahadasha lord, each describing the nine Antardashas inside it. Chapter 61 does the same for Pratyantardashas and opens with a caution that applies to all of it: the effects listed are general, and the unfavourable ones are not produced if the graha concerned is in a Trikona, lords an auspicious house, or sits in an auspicious house in a benefic Varga. Chapters 62 and 63 go on to a fourth and fifth level, Sukshma and Prana. The engine implements three levels and this calculator shows two.

Dasha and transit: the hour hand and the minute hand

Advanced Predictive Astrology offers a compact image for how the dasha sits beside the other timing layer in a chart. Dasha results, it says, are the hour hand of a clock and transit results the minute hand. The same passage lists what a reader is supposed to judge about the lords of the running dasha and sub-period before looking at transits at all: their significations, the houses they own, their associations and aspects, the house they occupy from the ascendant, whether they are exalted or debilitated, combust or retrograde, and the relation between the two lords. Only then are the transits at the time of assessment read. In this app the transit layer is the Gochar calculator, which reads all nine grahas from your natal Moon, and Saturn's long transit over the Moon has its own page at Sade Sati. The Timing feature is where the signed-in app brings the layers together.

Birth-time sensitivity, measured

The limits listed above the fold say that an unknown time read at noon moves the opening balance. The size of that movement is not small, and the sample date shows it unusually clearly, because 14 August 1994 is a day on which the Moon changes nakshatra. Here is the same date run through the engine at the two ends of the day and at noon.

Three people born on the same date, one just after midnight, one at noon and one just before the next midnight, have three different timelines. The first two share an opening lord but their Jupiter periods end eight and a half years apart. The third opens in a different lord entirely. And in October 2026 the midnight birth is in a different Mahadasha from the other two. The date-only answer is the middle row, and it is right only for someone born near noon.

A rule of thumb for your own chart

The shift in every boundary equals the opening lord's years multiplied by the Moon's movement during the time error, divided by 13 degrees 20 minutes. On the sample day the Moon covered 14.1 degrees in 24 hours, about 0.59 degrees an hour. One hour of birth-time error is therefore 4.4 per cent of a nakshatra.

• With Jupiter opening (16 years), one hour of error moves every date in the timeline by about 0.70 years, roughly eight and a half months. Four minutes moves them by about 17 days.
• With Venus opening (20 years), one hour is about 0.88 years, close to eleven months.
• With Ketu or Mars opening (7 years), one hour is about 0.31 years, under four months.
• With the Sun opening (6 years), one hour is about 0.26 years, a little over three months.

The shift is the same for all nine Mahadashas, because every later period is stacked on the end of the first. Antardasha dates inside a later Mahadasha move by that same amount. This is why the calculator's tagline says a birth time makes the dates right, and why a recorded time matters more here than almost anywhere else among the date-level calculators. If you do not have one, what to do when the birth time is unknown sets out what can and cannot be read. If you have a time and a place, the full chart at the birth chart tool uses them.

The same arithmetic applied to the Moon's own accuracy

The page's limits state that the Moon is computed from a series accurate to about 0.1 degree. Put that through the same formula: 0.1 degree is 0.75 per cent of a nakshatra. With Jupiter opening that is 0.12 years, about 44 days; with Venus about 55 days; with the Sun about 16 days. So even with a perfect birth time the boundaries are good to a matter of weeks, and the precision of the timestamps the engine returns should not be mistaken for accuracy. The same reasoning applies to the ayanamsa: a tool using a different ayanamsa places the Moon at a different sidereal longitude, and the difference passes straight into the balance. Why apps disagree on your nakshatra covers that case, and it is the first thing to check when another site's dasha dates differ from these.

What this calculator does not do

• It does not judge a period. Whether a lord is well or badly placed needs the ascendant and the houses, which a birth date cannot give.
• It does not show the third level. Pratyantardashas exist in the engine and follow the same proportional rule, but the result here ends at the Antardashas of the running Mahadasha.
• It does not show a range for a date-only birth. The Moon Sign and Nakshatra calculators report both ends of the birth day when no time is given; this one returns the noon reading alone, so the table in the section above is the comparison to keep in mind.
• It does not choose between dasha systems. BPHS names many others, each tied to a condition; six of them are checked against your chart on the Alternate Dashas calculator.
• It prescribes nothing. BPHS Ch. 47 ends with a ritual instruction for one case; this app does not reproduce remedies.

How it connects to the rest of the app

Vimshottari is a function of one number, the Moon's sidereal longitude, so the pages that describe the Moon are its natural neighbours. The Moon Sign calculator gives the sign and degree; the Nakshatra calculator gives the nakshatra, pada and lord, and that lord is your opening Mahadasha lord by definition. Moon sign and nakshatra explains how the two divisions of the same longitude relate.

The Nakshatra Sub-Lord calculator uses the same nine lords and the same proportions, but applied to arc instead of time: it divides a nakshatra's 13 degrees 20 minutes into nine unequal parts, starting from the nakshatra's own lord. BPHS gives the proportional rule for periods only, and the engine's notes say plainly that applying it to arc is an extension of the text, not a use of it.

Two other dasha calculators sit beside this one and should not be expected to agree with it. Chara Dasha assigns periods to signs, starting from the ascendant, with no balance removed at birth. Numerology Dasha is a numerology timing system built from the birth date's numbers, not from the Moon's position, and shares only the word. Further out, Career and Money dates its windows from this same Vimshottari timeline, and AI Life Chat is given the running Mahadasha and its classical reading as part of what it grounds answers in.

Questions people ask about Vimshottari Dasha

Why does the sequence start with Ketu here when BPHS starts with the Sun?

They are the same circle. BPHS Ch. 46 Sl. 12-14 counts nakshatras from Krittika, whose lord is the Sun. The engine counts from Ashwini, the first nakshatra, whose lord is Ketu. Krittika is the third nakshatra and the Sun is third in the engine's list, so every nakshatra gets the same lord either way. The worked example above shows both counts landing on Jupiter for Vishakha.

My dates here differ from another site by a few weeks. Which is right?

Possibly neither to the day. Three things move the dates: the ayanamsa used for the Moon, the accuracy of the Moon's computed position, and the length of year used to turn years into days. This engine uses Lahiri, a Moon position good to about a tenth of a degree, and a 365.2425-day year. A tenth of a degree alone is worth about two weeks in a Sun opening and nearly eight in a Venus opening. Compare the Moon's longitude first, using the Ayanamsa calculator to see the offset in use.

My dates differ from another site by years. What happened?

Almost always the birth time. If one tool had your time and the other read the date at noon, the Moon can be several degrees apart, and with a long opening lord each hour is worth most of a year. The other possibility is that the Moon sits near a nakshatra boundary and the two tools place it on opposite sides, which changes the opening lord itself.

Does the place of birth change the result?

Only through the clock. The Moon's longitude does not depend on where on Earth you were born, and the ascendant is not used. What a place contributes is the time zone, which converts your local birth time into the instant the Moon is computed for. A birth time interpreted in the wrong zone is a birth-time error of that many hours.

Is a Mahadasha of Saturn, Rahu or Ketu bad?

The sources do not say that. BPHS Ch. 47 gives each of the nine lords a favourable description and a difficult one, and what decides between them is the lord's sign and house in the individual chart. Ch. 48 Sl. 1 says outright that a natural malefic that is exalted and in an auspicious house does not give unfavourable results. A lord's name alone settles nothing, and this calculator, which sees only a birth date, makes no judgement either way.

If I am still in my first Mahadasha, are the Antardasha dates reliable?

Treat them with care. For the partial opening period the engine divides the time from birth to the period's end among all nine lords, where the classical rule would skip the sub-periods that had already passed before birth. The Mahadasha dates themselves are unaffected, and from the second Mahadasha onward the Antardasha dates follow the classical rule exactly.