Vimshottari Dasha Calculator

The Vimshottari system, in full

The calculator above needs your birth details because two of the three inputs are personal. The system itself is fixed, and worth reading first: 9 planetary lords share a 120-year cycle in a set order, each ruling for a set number of years. Shukra holds the longest stretch at 20 years — 16.7% of the whole cycle — and Surya the shortest at 6.

The 9 mahadashas and their lengths

The order never changes. Where you enter it does — which is what the calculator works out.

Which lord you are born under, by nakshatra

This is the part most people get wrong. Your first mahadasha is not decided by your birth date but by the nakshatra your Moon occupied, and each of the 27 nakshatras spans 13.33°. How far the Moon had travelled through it decides how much of that first period was already spent before you were born — so the same birth date at a different birth time can open on a different lord entirely.

Antardashas — the sub-periods inside each mahadasha

Every mahadasha subdivides into 9 antardashas running in the same order, starting from the mahadasha lord itself. Each sub-period lasts (mahadasha years × antardasha years) ÷ 120, which is why the same antardasha is a different length inside different mahadashas — 81 combinations in all. These are the windows a reading actually dates.

None of the above needs your birth details. What does is the only question that matters: where in this cycle you are standing right now, and when the next boundary falls. That comes off your Moon's exact longitude, which is why the form asks for a birth time rather than just a date.