Dasha (planetary period) literally means "stage or condition of life" or "border". In Jyotish Dasha indicates both the conditions one will experience in life . It shows introvert nature of individual. and the chronological boundaries of these stages.
The Dashas are indicators that particular karmas have matured and ready to be experienced by native. There are 32 different dasha systems described in "Brihat Parashara Hora". Vishmotary Dasha is the most widely used in India during last centuries.
Vishmottari Dasha allots varied periods of influence to each of the nine grahas in a fixed sequence, the entire cycle lasting 120 years. Mahadasha, - time allocated to each planet, is different for each planet: Ketu, - 7; Venus, - 20; Sun, - 6; Moon, - 10; Mars, - 7; Rahu, - 18; Jupiter, -16; Saturn, - 19; Mercury, - 17 years. While the order of Mahadashas in Vishmottari Dasha is fixed, the point in order where the sequence commence in a particular horoscope usually depends on the Nakshatra position of the Moon at the moment of birth. The planet which rules this Nakshatra is the first ruler of native's life and will continue to rule for that period allocated to it by the Vishmottari Dasha system, a portion which is proportioned to the distance the Moon has left to traverse within that Nakshatra.
Bhukti comes from root word "bhuj", meaning "to enjoy, participate in, consume". Mahadasha is divided into nine minor periods, which are each allotted to one graha, in the same order that characterizes the dasha. To determine the length of Bhukti use so-called Rule of Three: multiply the number of years allotted in the Vishmottari Dasha to the major period lord by the number of years allotted to the minor lord, then divide by ten and detach the reminder. The answer indicates the number of months in the minor period, and when the reminder is multiplied by three that answer indicates the number of days which must be added to the number of months to give the minor periods total length. Interpretation based on the Mahadashas help to evaluate general patterns of experience likely to unfold, while Bhukti permit dynamic interpretations which are usually more immediately meaningful.