Mahadasha vs Antardasha: A Worked Vimshottari Timeline

What is the difference between Mahadasha and Antardasha?

This guide explains the arithmetic of the common 120-year Vimshottari scheme. Other Dasha systems have their own rules. A period label is part of an astrological timing framework; it does not guarantee a particular event.

How an Antardasha gets its length

Each of the nine lords has a weight equal to its full Vimshottari Mahadasha length. The weights total 120. For a complete parent period, the calculation is:

Antardasha duration = full Mahadasha duration × subperiod lord's weight ÷ 120.

The first subperiod of a complete Mahadasha belongs to the same lord as the parent. Continue through the usual cycle and return to its beginning when necessary. P. V. R. Narasimha Rao's section 16.3 describes this proportional division and the treatment of a period already underway at birth.

For Venus–Rahu, use Venus's 20-year parent and Rahu's weight of 18: 20 × 18 ÷ 120 = 3 Dasha years. The parent name supplies the interval being divided; the child name supplies the fraction. Read both names before interpreting a printed duration.

A complete Venus Mahadasha, divided into nine parts

For clear arithmetic, the table uses model months: one model month is exactly one twelfth of whichever Dasha-year duration is selected. These are not Gregorian calendar months. A 20-year parent contains 240 of these units.

Venus–Venus receives 240 × 20 ÷ 120 = 40 model months. Venus–Sun receives 12; Venus–Rahu receives 36. The nine durations sum to 240, with each row beginning where the previous one ends.

The table's “Start” and “End” measure elapsed units from the true beginning of the parent period. They are not the person's ages. In this example, a boundary belongs to the period starting there: month 122 begins Venus–Jupiter and ends Venus–Rahu. A printed date without a time can conceal that transition.

Why the first Antardasha shown at birth may be Rahu, not Venus

Imagine a birth halfway through this Venus Mahadasha: 10 Dasha years, or 120 model months, have elapsed and 10 years remain. This is an invented teaching case. In the usual birth-balance method, a Moon halfway through a Venus-ruled Nakshatra would give this half-period balance.

Find 120 in the full table. It lies inside the Rahu interval, from 86 to 122. Only two model months of that Antardasha remain. Keep the original subperiod boundaries and display the part after birth:

The visible durations total 2 + 32 + 38 + 34 + 14 = 120 model months. That is the correct remainder of the 240-month parent. The first four Antardashas have already ended, so they are absent from this birth-onward view.

Do not divide the remaining ten years afresh and restart at Venus–Venus. That would create a new subdivision with different boundaries. The birth-balance guide explains the preceding step: deriving the remaining parent period from the Moon's position.

Where Pratyantardasha fits

Apply the same proportional idea inside a complete Antardasha. Within the full three-year Venus–Rahu interval, the Jupiter Pratyantardasha has duration 3 × 16 ÷ 120 = 0.4 Dasha year. A report that lists levels from large to small would label it Venus–Rahu–Jupiter.

The order inside Rahu's complete Antardasha starts with Rahu and proceeds through the cycle. Jupiter therefore follows Rahu there. A three-name label does not mean the first name has stopped operating; it identifies the parent, child and grandchild intervals together.

If birth occurs during one of those smaller intervals, the visible part is again clipped to the birth-onward window. More nested levels do not remove uncertainty in an imprecise birth time.

Why model years are not yet calendar dates

Durations become timestamps only after a year-length convention is chosen. One Dasha year taken as 360 days differs from one taken as 365.2425 days by 5.2425 days. The same proportional table can therefore produce different dated boundaries.

Astrogyana's current standard Kundli builder supplies 365.2425 days per Dasha year. Its timeline divides the full parent interval before limiting the displayed portion to birth onward. The methodology page provides calculation context. Do not infer these settings from a different program's name alone.

Our table has no real birth date and does not predict a calendar transition. To reproduce an actual endpoint, retain the birth timestamp, time zone, sidereal Moon longitude, ayanamsa, year length and rounding convention. A model month should not be added to a civil date as if every month had the same length.

A practical way to read your report

1. Confirm that the report says Vimshottari.
2. Read its legend to establish the order of the period names.
3. Locate the active major period and its underlying full duration.
4. Check whether the displayed first row begins at birth or at the true period start.
5. Compare the subperiod dates using the same display time zone.
6. Keep calculation questions separate from any traditional interpretation.

Use the Kundli result with the complete planetary inputs. The degrees and Nakshatra guide helps identify the Moon's coordinate correctly. When reports disagree, begin with those inputs instead of deciding that a dramatic period name must be the right one.

Frequently asked questions