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Astrology18 min readUpdated 9 Oct 2026

What a Mahadasha actually is, and how to find the one you are in

Vimshottari Dasha is a 120-year clock started by the Moon at your birth. Here is how the nine periods are built, why the sub-period usually matters more than the period, and a calculator that finds yours from your birth date.

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How this library is written

Every article is written from named sources - the classical texts listed on the Sources page and this product's own engine code. Where those sources disagree, the article says so; where they are silent, it does not fill the gap.

Not one number - the whole timeline

This page shows one layer. With an account you get every Mahadasha and Antardasha date, your Personal Year, and the full convergence of both systems in one place.

Open the full calculator

In depth

The index above is a list of titles. What follows is the reader's guide to it: why the topics run in the order they do, which book stands behind each shelf, how the small calculations that close the essays are actually worked, how to read every tile they can return, and what a missing birth time does to each of them. One birth date is carried through all five calculations so that the arithmetic can be checked by hand.

The order of the shelves is the order a chart is read

Brihat Parashara Hora Shastra begins its technical teaching with a distinction. In Ch. 3 Sl. 2-3 the lights in the sky that do not move are the nakshatras; in Sl. 4-6 the ones that move through them are the grahas. The same passage says the zodiac holds 27 nakshatras counted from Ashvini, that the same circle is also cut into 12 rashis counted from Mesha, that the rashi rising in the east is the Lagna, and that a person's results are worked out from the Lagna and the grahas together. Graha, rashi, nakshatra and Lagna: those four nouns are most of the library.

The text then takes them one at a time, and the topic chips keep close to its sequence. Ch. 3 describes the grahas and Ch. 4 the rashis. Ch. 11 lists what each of the twelve bhavas is judged for, and Ch. 12 to 23 go through the bhavas one by one. Ch. 24 places each bhava lord in each house. The dashas - the timing of all of it - arrive at Ch. 46, and Ch. 47 onward reads their effects. So the shelves run Planets, Signs, Houses, Nakshatras, Planet in house, Dashas - the order in which a chart is learnt - and Numerology follows as a separate tradition with its own books. A reader starting from nothing can open the Sun, then Aries, then the 1st house, then Ashwini, and meet the vocabulary in the order the text itself introduces it.

TopicOne page perPages plannedWhere the classical material sits
Planetsgraha, Sun to Ketu9BPHS Ch. 3; Saravali Ch. 4; Bhrigu Sutras Part I
Signsrashi, Aries to Pisces12BPHS Ch. 4; Saravali Ch. 3, and Ch. 22-29 for each graha in the signs
Housesbhava, 1st to 12th12BPHS Ch. 11 Sl. 2-13 and Ch. 12-23; Bhrigu Sutras Part II Ch. 1
Nakshatrasnakshatra, Ashwini to Revati27BPHS Ch. 3 Sl. 4-6 (27 from Ashvini; the names are in the note of the translator) and Ch. 46 (the dasha each one begins)
Planet in housegraha in a bhava, 9 x 12108Bhrigu Sutras Part II Ch. II-IX; Saravali Ch. 30; BPHS Ch. 24 for the lord
DashasMahadasha of each graha9BPHS Ch. 46-47 and Ch. 51-60; Saravali Ch. 41-42
Numerologynumber, 1 to 99the numerology books named on the Sources page
The reference library as planned. The count printed at the top of this page is what is published today; the plan is filled in one written page at a time.

Beside the reference shelves sit fifteen essays, filed under Astrology, Numerology, Accuracy and Method. They are ordered by hand, and the first ones answer a question a visitor usually arrives already holding: what a Mahadasha is, what to do without a birth time, and how the Moon sign differs from the nakshatra. Reference pages tell you what a thing is; essays tell you what to do with it.

Which book answers which question, and where the books part

The Sources page lists the texts. What it cannot show is how unevenly they divide the work, and that matters for reading a page here. BPHS has no chapter that takes the nine grahas one by one through the twelve houses. Its bhava chapters (Ch. 12-23) judge a house by its lord, its occupants and the aspects on it, Ch. 24 gives each lord in each house, and a single placement is named outright only in passing - the Sun in the 2nd, for instance, in Ch. 42. The ready-made graha-in-bhava paragraph is the method of two other books: Saravali Ch. 30, 'Effects of Planets in Bhavas', and Bhrigu Sutras, which gives one chapter to each graha in the twelve houses, with Rahu and Ketu sharing the last. That is why a page such as Sun in the 2nd house cites three books for three different things, and why it is longer than a single quotation would make it.

When two books describe the same placement differently

Take the Sun in the first house. Saravali Ch. 30 Sl. 2 reads it as a prominent and honourable personality that is also slow to act, quick to anger, courageous and impatient. Bhrigu Sutras, in its Sutras 1-21 on the same placement, calls the person wise, well conducted, sparing of speech and happy - and inside that one passage describes the same person as both lacking knowledge and highly intelligent. Each book then changes its reading by the sign the Sun occupies. A library that merged these into one confident paragraph would be inventing an agreement the sources do not have. The rule here is to give each statement with its reference and to say where they differ; the page for this placement is Sun in the 1st house.

When the engine is simpler than the text

BPHS Ch. 3 Sl. 11 sorts the grahas: the Sun, Saturn, Mars, the waning Moon, Rahu and Ketu are malefic, the rest benefic, and Mercury turns malefic when it joins a malefic. The tone this product attaches to a Mahadasha lord on the article pages is coarser, by choice. In the code (lordTone) Jupiter, Venus, Mercury and the Moon are 'favourable'; Saturn, Rahu and Ketu are 'testing'; the Sun and Mars are 'mixed'. It does not look at the Moon's phase or at Mercury's company, and it places the Sun and Mars in the middle where Parashara places them with the malefics. So the word 'favourable' on a tile is this product's stated convention, not a quotation from Ch. 3.

When the books disagree with each other about a formula

The Personal Year is the clearest case. Advanced Vedic Numerology prints two methods on one page: a 'Vedic' one (the Moolank, plus the birth month, plus the two-digit year, plus the number of the weekday lord of that year's birthday, running from birthday to birthday) and a 'Western' one (birth day plus birth month plus the four-digit year). Numerology Made Easy adds the birth month and day to what it calls the Universal Year and also starts the year on the birthday, with its own rule for which calendar year enters the sum when the birthday falls after 30 June. This engine uses the Western sum and changes the number on 1 January. That is four ways of arriving at one number, differing in the sum or in the day the year turns: a different figure on another site is usually one of these conventions and not an error. The Personal Year essay works through it, and the Personal Year calculator shows the months and days underneath.

The five calculations behind the essays

Five essays end in a small form with a date field and an optional time field. All five send the same request to the same public endpoint and receive the same answer; each shows a different slice of it. Only the date and, if typed, the time are sent. No name and no place are asked for, so two assumptions are always in force and are printed with the result: when the time is blank the chart is cast for 12:00 noon, and because there is no place the clock is read as Indian Standard Time. Houses are deliberately not computed for this request, which means nothing on these five pages depends on the Ascendant.

Mahadasha

The engine finds the Moon's sidereal longitude at birth, divides it by 13 degrees 20 minutes to get the nakshatra, and takes that nakshatra's number modulo nine to pick the first lord from the fixed cycle Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17 - 120 years in all. BPHS Ch. 46 Sl. 12-14 states the same wheel starting at Krittika with the Sun; counting from Ashwini with Ketu enters the wheel two places earlier and lands on the same lord. Sl. 15 gives the years. Sl. 16 gives the balance at birth: the expired part of the first dasha is its length multiplied by the share of the nakshatra the Moon has already crossed. The engine does exactly that, with a year of 365.2425 days.

Sub-periods follow BPHS Ch. 51 Sl. 1-2: an antardasha lasts the product of the two lords' years divided by 120, and the first one in any Mahadasha belongs to the Mahadasha lord itself. One step is this product's own. The essay tile does not show the Mahadasha running this minute; it shows the one that covers the largest share of the next twelve months, so that a period ending next week does not headline a year. The percentage beside the lord is that share.

Whether the birth time matters

When the time field is blank, the engine casts the chart twice more - at 00:00 and at 23:59 on the birth date - and asks which Mahadasha each of those charts puts today in. If both give the same lord, the noon assumption changed nothing about the headline. If they differ, both lords are named. This is a test run on your date, not a general caution.

Personal Year

Birth day plus birth month plus the current calendar year, reduced by adding digits until one digit is left; master numbers such as 11 and 22 are not kept here. 'Right now' is this calendar year's number, read on an Indian clock. 'Next' is the number that will be in force twelve months from today. The birth year, time and place are not inputs.

What both systems say

The Mahadasha lord and the Personal Year each already carry a tone in the engine. The consensus slice renames those tones onto one three-step scale so that agreement becomes an equality check on two independently computed values.

Engine toneMahadasha lordPersonal YearStancePrinted meaning
favourableJupiter, Venus, Mercury, Moon1, 3, 5, 8expandstart new things and push outward
mixedSun, Mars2, 4, 6, 7buildconsolidate and work on what already exists
testingSaturn, Rahu, Ketu-holdprotect what you have rather than force a new start
closing-9holdthe same hold stance
From lordTone(), personalYearTone() and STANCE_BY_TONE. A convention of this product, stated so it can be argued with.

Expand, build and hold are ranked 2, 1 and 0. A difference of zero is 'Both agree', one is 'Not fully agreed', two is 'Directly opposed'. Where the two differ, the more cautious stance is reported as the one to act on and the split is named, not averaged. Because the window is twelve months and the Personal Year changes on 1 January, most windows span two Personal Years; the one covering more of the window sets the numerology stance.

Moon sign and nakshatra

The same longitude, cut two ways: divided by 30 degrees it gives the rashi counted from Aries, divided by 13 degrees 20 minutes it gives the nakshatra counted from Ashwini. With no time typed, both are read from the noon chart.

Essays that end in a full calculator instead

The other ten essays, and the reference pages, end in one calculator from the catalogue. Whether it runs on the article page is decided by what that calculator needs, not by the article. If it needs only a birth date, a date with a time, or a calendar day, it runs in place: the Vimshottari dasha, life path and Lo Shu grid calculators run from a date, and the ayanamsa calculator from a day. The nakshatra sub-lord and Kaal Sarp calculators need the time as well, and on an article page that time is read as IST because no place is collected.

Anything that rests on the Ascendant gets a card and a link in place of a form: the Navamsa, Mangal dosha, yogas and birth chart calculators run on their own pages, where the birth place is picked from suggestions and its coordinates and time zone are resolved properly. An article never asks for a name, a place or coordinates, and a calculator that needs one is not squeezed to fit. A reference page may also end with no calculator at all, when nothing in the catalogue computes its subject.

Reading each result, tile by tile

Essay endingWhat appearsHow to read it
The Mahadasha you are running'Mahadasha lord' with a percentage; 'Runs' with two dates; 'Sub-period now' with its dates; one sentenceThe percentage is the share of the next twelve months that lord covers. Below 100, a Mahadasha changes inside the year. The sentence names the date the sub-period hands over if one falls in the window, or says the sub-period runs throughout.
Whether birth time matters for your date'Does it change it?' with one of three answers; then either 'The two candidates' or the Mahadasha lord'You gave a time, so the question is settled'; 'Not on this date' (both ends of the day agree); or 'Yes, on this date it does', followed by the early-birth lord and the late-birth lord.
Your Personal Year'Right now', 'Next', and 'Changes on' when the two differ; a meaning sentence; a line naming the dominant yearThe first number is this calendar year. The meaning sentence describes whichever year covers more of the next twelve months, so late in a year it already describes the next number.
What both systems say about your next 12 monthsA tag; 'Astrology reads' with a stance and the lord; 'Numerology reads' with a stance and the number; a verdict sentenceThe tag is the distance between the two stances. The sentence gives the operative stance - the shared one, or the more cautious one when they differ.
Your Moon sign and nakshatra'Moon sign' and 'Birth nakshatra'Read from the minute you typed, or from noon when you typed none. The card beneath says which.

Under every result sits a card headed 'How exact this answer is'. For four of the five it is green when a time was given and amber when noon was assumed, and its text is the sentence the engine wrote after testing both ends of your birth day. Under the Personal Year it carries a fixed statement instead, because time and place are not inputs to that sum. A last card, 'Where does this number come from?', says in three sentences that the astrology line and the numerology line are computed separately and compared afterwards.

One birth date through all five

Take 14 August 1994 with no time and no place - a sample date, not a person - and read it at noon IST on 5 October 2026. Everything below is what the engine returned for that request; dates are the UTC calendar dates in the response.

  1. Moon. The noon Moon stands at 207.76 degrees of the sidereal zodiac. Divided by 30 that is the seventh sign with 27.76 degrees used: Libra. Divided by 13 degrees 20 minutes it falls in the sixteenth nakshatra, which runs from 200 degrees to 213 degrees 20 minutes: Vishakha, third pada. The tiles read 'Libra' and 'Vishakha'.
  2. First lord. Vishakha is number 15 counting Ashwini as 0; 15 modulo 9 leaves 6, and the entry at position 6 of the cycle is Jupiter, 16 years. Counting Parashara's way, Vishakha is the fourteenth nakshatra from Krittika; 14 divided by 9 leaves 5, and the fifth lord in his list - Sun, Moon, Mars, Rahu, Jupiter - is again Jupiter.
  3. Balance. The Moon has crossed 7.76 of the 13.33 degrees of Vishakha, a share of 0.582. The unexpired share is 0.418, and 16 years times 0.418 is 6.69 years. Jupiter therefore runs from birth to 23 April 2001.
  4. Timeline. Saturn takes the next 19 years, to 22 April 2020. Mercury takes 17, to 22 April 2037. On 5 October 2026 the Mahadasha is Mercury, and it covers the whole of the next twelve months: the tile reads Mercury, 100%.
  5. Sub-period. Inside Mercury the order is Mercury, Ketu, Venus, Sun, Moon. The Sun's share is 17 times 6 divided by 120, or 0.85 of a year - about 310 days - and the engine places it from 17 July 2026 to 23 May 2027. Its sentence: 'Mercury Mahadasha covers 100% of the next 12 months, with the Sun sub-period handing over to Moon on 2027-05-23.'
  6. Personal Year. 14 + 8 + 2026 = 2048; 2 + 0 + 4 + 8 = 14; 1 + 4 = 5. For 2027 the sum is 2049, then 15, then 6. The tiles read 'Right now 5', 'Next 6', 'Changes on 1 Jan 2027'.
  7. Consensus. From 5 October 2026 the window holds about 88 days of 2026 and about 277 days of 2027, so Personal Year 6 is dominant: tone mixed, stance build. Mercury is favourable: stance expand. The stances are one step apart, so the tag is 'Not fully agreed' and the sentence reads: 'The two systems do not fully agree. Astrology reads expand, numerology reads build. Where they split, the more cautious of the two is the one to act on: build - consolidate and work on what already exists.'
  8. Birth time. The tile answers 'Yes, on this date it does' and names Saturn / Mercury. The amber card says a birth early on that date gives a Saturn Mahadasha and a birth late in the day gives Mercury, and adds that IST was assumed.

Two Personal Years in one answer

The same response also carries a 'right now' working of four layers. For this date they are the astrology Mahadasha, Mercury (favourable); a separate numerology Mahadasha, Mars (mixed); Personal Year 5 (favourable); and the second Pinnacle cycle, which is not rated. The full free reading prints the two numerology layers that the article tiles leave out. That working counts Personal Year 5 because it describes today; the twelve-month verdict above counts 6 because it describes the window. Both are right for the question each one answers.

What one day of uncertainty contains

The birth-time tile compresses a great deal into one line. Here is the same date cast at six different times, each read on 5 October 2026.

Birth time (IST)MoonNakshatra and padaFirst dasha endsMahadasha on 5 Oct 2026
00:00Libra 20.70Vishakha 1Jupiter, 12 Oct 2009Saturn, 2009 to 2028
06:42Libra 24.64Vishakha 2Jupiter, 18 Jan 2005Mercury, 2024 to 2041
12:00Libra 27.76Vishakha 3Jupiter, 23 Apr 2001Mercury, 2020 to 2037
16:00Scorpio 0.11Vishakha 4Jupiter, 27 Jun 1998Mercury, 2017 to 2034
22:00Scorpio 3.63Anuradha 1Saturn, 11 Mar 2013Mercury, 2013 to 2030
23:59Scorpio 4.80Anuradha 1Saturn, 14 Jul 2011Mercury, 2011 to 2028
computeChart() for 14 August 1994 at each time, IST assumed. Degrees are within the sign.

Stepping through that day a minute at a time, three things change. At 02:52 the Mahadasha read today turns from Saturn to Mercury. At 15:49 the Moon leaves Libra for Scorpio. At 21:30 it leaves Vishakha for Anuradha, and the first dasha of the life becomes Saturn's and not Jupiter's. The Moon covered 14.10 degrees between the two ends of the day. Even across the hours in which the lord's name holds, the Mercury period's start slides from late 2026 back to July 2011 - fifteen years. So when the tile answers 'Not on this date', it means the lord's name is safe. The dates printed beside that name are still noon dates, and a birth time moves them.

The reason is arithmetic. A nakshatra is 13 degrees 20 minutes wide and the Moon covers roughly that in a day, so an unknown time can move the Moon across nearly a whole nakshatra, and the balance of the first dasha with it - up to 20 years when that dasha is Venus's. Running every birth date of 1994 through the same engine, read on 5 October 2026 with IST assumed: the Mahadasha differed between the two ends of the day on 283 of 365 dates; the Moon changed sign on 161 and nakshatra on 349; and the Moon's arc across a day ranged from 11.77 to 15.22 degrees. Those are counts of calendar dates from this engine for one birth year read on one day, not a statement about people. On the same run the twelve-month verdict was 'Both agree' for 121 dates, 'Not fully agreed' for 168 and 'Directly opposed' for 76 - agreement is not the default result.

  • The Moon tiles show the noon position only. The Moon sign and nakshatra calculators report both ends of a date-only birth day and say whether they differ.
  • The clock is IST unless a place is given. A birth outside India should be run on the full reading or on a calculator page, where the place supplies the zone.
  • The astronomy is computed from published formulae (Meeus), with the Lahiri ayanamsa; the Moon is good to about 0.1 to 0.3 degrees. It is not Swiss Ephemeris, and the methodology page says so. Within a fraction of a degree of a boundary, another program can fairly print the neighbouring nakshatra - the subject of why apps disagree on your nakshatra.
  • Dates in the engine's sentences are UTC calendar dates; the tiles print the same instants in your browser's zone, so a boundary late in the UTC day can appear as the next date in India.
  • Nothing on these five pages uses the Ascendant. The translator's note to BPHS Ch. 3 gives the reason it cannot be guessed: a rashi takes about two hours to rise and a degree about four minutes, varying with latitude. Anything built on it belongs to the Lagna calculator and its neighbours.
  • Birth dates before 1900 and dates in the future are refused, and the response says why.

What a tile cannot tell you

BPHS Ch. 47 Sl. 2 says the effects of a dasha are of two kinds: general, from the graha's own nature, and distinctive, from its placement. Sl. 3-4 add that the effects follow the graha's strength, and Sl. 5-6 that they are favourable when the dasha lord sits in the Lagna, in exaltation or in its own sign, and unfavourable when it sits in the 6th, 8th or 12th, in debilitation or in an enemy's sign. The article tile knows only the lord's name. At most it is the general half, flattened into three words. The distinctive half needs the whole chart: the Kundali feature places the lord, the Shad Bala calculator weighs it, and the timing feature lays every Mahadasha and Antardasha on dates. A Saturn period is printed as 'testing' here whether that chart's Saturn is strong or weak, and the reader should know it.

  • No remedies, gemstones, mantras or rituals are prescribed anywhere in the library. Where a classical text names one, the page does not pass it on.
  • Classical statements about the body are reported as what the text says and are not medical advice.
  • Article text is English at present; the labels, buttons and tile headings follow the language you chose.
  • Nothing typed into an article is stored, and no account is created. The request is sent as a POST so that a birth date never sits in a URL.

Where to start, by the question you came with

Questions about the library and its calculations

Do I need an account to run the calculation at the end of an article?
No. The form sends a birth date, and a time if you typed one, to a public endpoint that computes the answer and returns it. It stores nothing, creates no account and asks for no email. The request is rate-limited per address, so a very large number of dates in a few minutes will be asked to wait.
Why does an article ask only for a date when a kundali needs time and place?
Because the five inline results rest on the Moon and on the calendar date, not on the Ascendant. The Moon's nakshatra fixes the Vimshottari sequence (BPHS Ch. 46 Sl. 12-16), and the Personal Year uses only day and month. Anything that needs houses runs on its own page - start with the birth chart calculator.
The page says my birth time matters. What should I do?
Type the time into the optional field and run it again; the amber card turns green and the two candidates collapse to one. If you only know the time roughly, note which of the two lords the early and late ends of the day give - the tile names them in that order - and treat the dates as provisional until a time is found.
Why is my Personal Year here different from the one another site gave me?
Most often because of the day the year turns. This engine changes the number on 1 January. Numerology Made Easy and the Vedic method in Advanced Vedic Numerology both run the year from birthday to birthday, and that Vedic method also adds a weekday number. So for part of every calendar year a birthday-based method prints a different figure from a 1 January one.
Why does the twelve-month verdict use a different Personal Year from the one shown as Right now?
The verdict describes a window, not a day. It takes whichever Personal Year covers more of the next twelve months. Read in October, about three quarters of that window lies in the next calendar year, so the next number sets the stance while 'Right now' still shows this year's.
Is 'favourable' a classical judgement of my Mahadasha?
No. It is a three-way sorting of the nine lords that this product applies by name alone. BPHS Ch. 3 Sl. 11 sorts them differently, and Ch. 47 Sl. 2-6 makes the result depend on the lord's strength and placement in your chart, which the article tile does not read.
Which ayanamsa and which astronomy does the library use?
Lahiri (Chitrapaksha) ayanamsa, with Sun and Moon positions computed from the formulae in Meeus, Astronomical Algorithms. It is not Swiss Ephemeris. The ayanamsa calculator shows the value used for any day.
Will the result change if I come back later?
The birth-side facts do not: Moon sign, nakshatra and the dasha dates stay as they are. The window does. The twelve months start from the day you ask, so the coverage percentage, the sub-period named, the dominant Personal Year and therefore the verdict can all move as the window slides forward.
When two books disagree about a placement, which one does the article follow?
Neither is silently preferred. The page gives each statement with its chapter and sloka or sutra, says where they differ, and stops where both are silent. The provenance note at the top of each article file lists every passage and every engine function used.