What is Vimshottari Dasha?
Vimshottari Dasha is the timing framework most Vedic astrologers reach for first. It splits a notional 120-year span into nine planetary periods, each ruled by one graha, and runs them in a fixed order — Ketu, Venus, Sun, Moon, Mars, Rahu, Jupiter, Saturn, Mercury. Which period you are born into, and how far through it, is set by the Moon's Nakshatra at the exact moment of birth, so the whole sequence is anchored to your own details.
The idea is not that a planet forces events, but that it sets the prevailing tone of a stretch of life, which the rest of the chart then shapes. Astrovarg computes these periods from real planetary positions — the Moon’s longitude at your birth instant, resolved on the engine, not approximated in your browser.
Mahadasha and Antardasha
A Mahadasha is the major period — the headline planet governing a run of years. The lengths are fixed: the Sun rules six, the Moon ten, Jupiter sixteen, Saturn nineteen, Venus twenty, and so on to 120 in all. Inside each Mahadasha the same nine planets take their turn again as Antardashas, or sub-periods, and each Antardasha subdivides once more into Pratyantardashas.
Reading them as layers is the point: the Mahadasha sets the theme, the Antardasha colours the current chapter, and the finer levels mark the shorter turns within it. A planet that is well placed in your chart tends to give an easier period, while a difficult one asks for more care.
Why accurate birth time matters
Dasha timing is only as reliable as the birth time behind it. The Moon travels roughly one Nakshatra a day, so a shift of a few minutes near a boundary can change the Nakshatra it occupies — and with it the balance of your very first period and every date that follows. An approximate time produces an approximate timeline.
If your recorded time is uncertain, treat the period dates as indicative rather than exact, and consider birth-time rectification before leaning on them for important planning. It is also why the calculator asks for date, time and place together: all three define the sky it works from.
Which ayanamsha is used
Sidereal calculations depend on the ayanamsha — the slowly shifting offset between the tropical and sidereal zodiacs. This page defaults to Lahiri, the standard for mainstream Vedic work and the most widely published, so your dates line up with common references. Other systems, such as Raman, move the boundaries slightly and can nudge a Nakshatra edge, which is why the ayanamsha is shown as a field rather than hidden. The KP-specific ayanamshas belong with the KP tools and are not the default here.