What Is Mahadasha? Vimshottari Periods, Balance and Antardasha

The complete sequence

Vimshottari divides a nominal 120-year cycle among nine lords: Ketu 7 years, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19 and Mercury 17. The order repeats after Mercury. These unequal durations are part of the traditional framework. A Mahadasha is a major period; an Antardasha is a sub-period inside it. Neither term means that a particular event must happen during those dates.

How the first lord is selected

The birth Moon’s Nakshatra identifies the initial lord. Each equal Nakshatra spans 13°20′. Its unelapsed fraction determines how much of the first Mahadasha remains at birth. A person is therefore rarely born at the beginning of a complete major period. A timeline may show the full period starting before birth, which is useful for explaining the arithmetic, but only the remaining balance belongs to the person’s post-birth timeline.

A balance example

Suppose a hypothetical Moon is exactly halfway through a Venus-ruled Nakshatra. Venus has 20 allotted years, so half the period, or 10 years under the selected year convention, remains at birth. If the Moon were three quarters through the same Nakshatra, five years would remain. This example isolates the proportional rule; it is not a forecast about the person’s relationships or possessions. The actual calculation uses the full longitude rather than rounding the position to a whole degree first.

Why software can disagree about dates

One program may use a 360-day year while another uses a mean solar or Gregorian year. getVEDANGA uses 365.2425 days. Ayanamsa choice, Moon-position precision and the recorded birth time can also shift the balance. At a Nakshatra boundary, the starting lord itself changes. Compare these settings before assuming that two different date lists indicate a broken calculator. The method should state its convention, and uncertainty should remain visible in the result.

Opening the Antardashas

Sub-periods are proportional to the allotted years of the major and minor lords. A Venus–Sun Antardasha in a full 20-year Venus period has a duration of 20 × 6 ÷ 120 years, or one year under the chosen convention. Each major period begins its sub-period sequence with its own lord. The tool shows these nested dates so the reader can follow the logic instead of accepting a mysterious timeline. Interpreting them requires more context than simply attaching an event to a planet.

Distinguish the complete cycle from the birth balance

The nine full allotted periods sum to 120 years, but a person is born partway through the first one. A display of that complete sequence can therefore begin before birth and end less than 120 years after it. A display covering exactly 120 years after birth would need part of another repeated period. Both views can be labelled clearly, but they should not be confused. Read the first start date, the birth balance and the chosen timeline convention together before interpreting the length of the visible sequence.

Try a small learning exercise

Pick a hypothetical Moon position within a Nakshatra and calculate the unelapsed fraction. Multiply it by the allotted years of the first lord, then write the year-length convention beside the answer. For one Antardasha, multiply the two lords’ allotted years and divide by 120. Compare the arithmetic with the displayed timeline before attaching an interpretation. If the input time is uncertain, repeat the calculation at the ends of the possible interval and keep both results visible. This makes the balance rule concrete without pretending to predict an event.

The method used on this site

The birth Nakshatra selects the first lord. The remaining fraction determines the balance. This implementation uses a mean Gregorian year of 365.2425 days; software using 360-day years can show different dates.

Frequently asked questions

Sources and further context

• getVEDANGA methodology — the implementation and its limits
• Astronomy Engine — astronomical calculations and validation
• Sanskrit Documents — Jyotisha texts and editions (traditional context)

Sources have different roles: astronomical documentation supports the calculation, while traditional texts describe a historical framework. A citation does not by itself validate a personal prediction.