Pratyantardasha: the third level of dasha
A pratyantardasha is the third level of the Vimshottari cycle, a sub-period inside an antardasha. The same proportional rule applies at each level.
What it is
Inside an antardasha of N years, a pratyantar of graha M lasts N times M divided by 120. Because the years shrink at each level, a pratyantar is usually a few weeks to a few months.
How it is worked out or read
The tool computes mahadasha and antardasha on the timeline. Pratyantardashas are not listed on this site yet; the arithmetic is given so that you can check a value by hand.
Where it appears on this site
Pratyantardashas are not yet in the dasha tool. The mahadasha and antardasha article gives the method for the two levels that are shown.
The third level of the cycle
A pratyantardasha is the third level of the Vimshottari cycle, a sub-period inside an antardasha. It is found by the same proportional rule: the antardasha's years multiplied by the pratyantar lord's years, divided by 120. Because each level shrinks the years, a pratyantardasha is usually a few weeks to several months long. The idea is that a very fine timing of the theme can be read at this level, but it is also the level where the timing becomes least certain, because the small periods are sensitive to the exact start.
The structure is recursive. The same nine-graha order repeats at every level, starting from the lord of the level above. A pratyantar in a Sun antardasha therefore begins with the Sun and then moves through the other grahas in the Vimshottari order, each lasting a fraction of the antardasha.
Why the finest level needs care
Because pratyantardashas are short, a small error in the birth time, in the Moon's position or in the ayanamsa can move the boundary between two of them by days. A reader who uses this level should check the boundary dates carefully, and should not treat a pratyantar as a precise event marker. The timing is an approximation of when a theme is active, and the reader should describe it in those terms.
The finer the level, the more the reading depends on the exact input. A reader who has a reliable birth time and a clear Moon position can use the pratyantar with more confidence than one who has an approximate time. The site presents the higher levels by default and notes the limits of the finer levels.
Checking a pratyantar by hand
To check a pratyantardasha by hand, take the antardasha's start date and length, then the pratyantar lord's years, multiply the antardasha length by those years, and divide by 120. Add the result to the start date, and then continue in the order of the nine grahas. The checks should match the dates from a tool that computes the full timeline, within the rounding used by the calculation.
The pratyantardasha is not in the dasha tool yet. The method is given so that a reader can compute it, and the mahadasha and antardasha article gives the same rule at the levels that the site does show.