The 120-year planetary clock
Vimshottari dasha is the main timing system of Vedic astrology: a fixed 120-year cycle divided among nine planetary periods called mahadashas. Which period you start life in — and how much of it remains — is set by the Moon's nakshatra at your birth. Each mahadasha foregrounds one planet's themes from your chart for a span of 6 to 20 years.
The name itself means 'one hundred and twenty' (vimshottari) — the idealized full human lifespan in classical texts. Nobody lives through the whole wheel from their own starting point twice; the point is not the total but the sequence, which tells an astrologer which planet currently holds the microphone.
The nine lords and their years
The cycle always runs in the same fixed order, and each lord's share of the 120 years never changes:
- Ketu — 7 years
- Venus — 20 years
- Sun — 6 years
- Moon — 10 years
- Mars — 7 years
- Rahu — 18 years
- Jupiter — 16 years
- Saturn — 19 years
- Mercury — 17 years
How your starting point is computed
Each of the 27 nakshatras is ruled by one of these nine planets, repeating in the same Ketu-to-Mercury order three times around the zodiac. The lord of the nakshatra your Moon occupied at birth is your first mahadasha lord. How far the Moon had travelled through that nakshatra sets the balance: enter it early and you begin with most of that period remaining, enter late and the next lord takes over within a few years.
This is pure arithmetic on one number — the Moon's exact sidereal longitude at birth. MyAstro360 computes it with the Swiss Ephemeris using the Lahiri (Chitrapaksha) ayanamsa, the standard reference of Indian panchangs. The calculation is deterministic: the same birth date, time, and place always produce the same dasha timeline. What varies between astrologers is interpretation, never the math.
Antardashas — periods within periods
Each mahadasha is subdivided into nine antardashas (sub-periods), one for every planet, in the same fixed order and beginning with the mahadasha lord itself. Their lengths are proportional to the mahadasha shares: an antardasha lasts the mahadasha's length multiplied by the sub-lord's years, divided by 120. So within Venus's 20-year mahadasha, the Venus antardasha runs 20 × 20 ÷ 120 — three years and four months — while the Sun antardasha lasts just one year.
In practice astrologers read the mahadasha as the chapter and the antardasha as the paragraph: the sub-lord colors, moderates, or amplifies the main lord's themes. Finer subdivisions (pratyantar and beyond) exist, but the mahadasha-antardasha pair carries most of the interpretive weight.
Reading a dasha without the doom
A dasha does not import a planet's textbook reputation wholesale — it activates that planet as it actually sits in your chart. Saturn mahadasha for someone with a well-placed Saturn is classically a period of consolidation, discipline, and earned authority. Rahu's 18 years often coincide with unconventional growth, relocation, or ambition that wouldn't fit an ordinary script. The lord's house, sign, aspects, and lordships decide the flavor; the period only sets the timing.
Two honest caveats. First, dasha analysis is interpretation, not fact — a lens tradition offers for reflection, not a verdict about what will happen. Second, the timeline is only as accurate as the birth time behind it: the Moon moves about a degree every two hours, and near a nakshatra boundary a small error in birth time can shift the entire sequence. If big life chapters seem offset from your computed dasha dates, an uncertain birth time is the usual suspect.