How is the starting dasha decided?

By the Moon's nakshatra at birth. The planet ruling that nakshatra gives your first mahadasha, and the fraction of the nakshatra the Moon had already crossed decides how much of that period was spent before birth. From there the remaining planets follow in fixed order for a 120-year cycle.

What is the difference between mahadasha and antardasha?

A mahadasha is the major period of one planet, lasting between 6 and 20 years, and it sets the broad theme of that stretch of life. Each mahadasha is subdivided into nine antardashas, shorter sub-periods ruled by each planet in turn, which colour how the main theme plays out month to month and year to year. Predictions read the two together.

How many years does each planet's dasha last?

The fixed spans are Ketu 7 years, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19 and Mercury 17, totalling exactly 120 years. Everyone gets the same spans in the same order; what differs is where in the cycle each person's life begins.

Is Saturn or Rahu mahadasha always difficult?

No. A dasha delivers what that planet promises in your specific chart, so a well-placed Saturn period often brings the most solid achievements of a lifetime. Difficult reputations belong to afflicted placements, not to planets in general, and every dasha is better read from your own chart than from a generic label.

Vimshottari Dasha Guide, Mahadasha and Antardasha Explained with All Planet Period Years

Vimshottari dasha is the master timing system of Vedic astrology: a fixed 120-year cycle in which nine planets take turns ruling periods of your life, from the Sun's 6 years to Venus's 20. Which period you are born into, and therefore which planet is running your life right now, is set entirely by the Moon's nakshatra at your birth.

If a birth chart is a photograph of the sky, the dasha system is the film that plays it forward. Here is how to read it.

The 120-year cycle: order and years

The nine planets rule in a fixed sequence with fixed durations:

Order	Planet	Mahadasha years
1	Ketu	7
2	Venus	20
3	Sun	6
4	Moon	10
5	Mars	7
6	Rahu	18
7	Jupiter	16
8	Saturn	19
9	Mercury	17

Total: 120 years, the traditional full human lifespan, which is what "vimshottari" (one hundred and twenty) means. The order never changes and the spans never change. What makes every life different is the entry point.

Your starting dasha comes from the Moon's nakshatra

Each of the 27 nakshatras is ruled by one of these nine planets, in the same repeating sequence as the table above. The nakshatra your Moon occupied at birth hands you your first mahadasha: born under Krittika, Uttara Phalguni or Uttara Ashadha (Sun-ruled stars), you begin life in a Sun mahadasha; born under Rohini, Hasta or Shravana, you begin under the Moon.

There is one more refinement. The Moon is always partway through a nakshatra at birth, and that fraction decides how much of the first dasha remains. If your Moon had crossed 60 percent of a Venus-ruled star, only 40 percent of the 20-year Venus period, 8 years, remains at birth. After that, the sequence simply rolls: Sun 6, Moon 10, Mars 7, and so on. This is why exact birth time matters so much; a small shift in the Moon's position can move your dasha boundaries by months.

The free vimshottari dasha calculator works all of this out from your birth details and shows your full timeline.

Mahadasha and antardasha: reading the two clocks together

A mahadasha sets the chapter; the antardasha writes the paragraphs. Every mahadasha is subdivided into nine antardashas (also called bhuktis), one for each planet in the same fixed order, starting with the mahadasha lord's own sub-period. Each antardasha's length is proportional: Venus's sub-period inside any mahadasha is the longest, the Sun's the shortest.

In practice, astrologers read the pair as "Saturn-Venus" or "Jupiter-Mercury": the mahadasha lord gives the broad agenda, career consolidation under Saturn, expansion and learning under Jupiter, and the antardasha lord decides which rooms of that house get the light. A Jupiter mahadasha with a Venus antardasha often flavours the growth with relationships, comforts and creativity; the same Jupiter period under a Saturn antardasha turns the growth toward structure and hard-won responsibility.

Two rules keep the reading honest:

The planet delivers what it promises in your chart, not its generic reputation. A Saturn period with a strong, well-placed natal Saturn frequently brings a person's most durable achievements. Rahu's 18 years, feared in gossip, are ambitious and worldly for many charts.
Junctions matter. The months where one mahadasha hands over to the next, called dasha sandhi, are classic times of transition, career changes, moves, shifts of focus, and they reward patience more than big launches.

What your current dasha can actually tell you

Knowing you are in, say, Rahu-Jupiter does not predict single events, but it does describe the weather: which areas of life are activated, which planet's placements in your chart are being tested or rewarded, and roughly when the theme changes. Matched against the houses those planets rule for your ascendant, it becomes genuinely practical, when to push a career move, when a relationship phase opens, when to consolidate instead of expand.

Run your timeline on the vimshottari dasha calculator, note your current maha and antar lords, and if you want them read against your actual chart, houses, aspects and all, you can talk to a guru at AstroLagnam in Tamil, Telugu, Hindi or English, first 3 minutes free. A dasha is a season to understand, not a sentence to serve.