Hindu mythologies have divided each world cycle into four yugas or world ages.
These are comparable to the four ages of the Greco-Roman tradition and, like the latter, decline in moral excellence as the round proceeds. The Classical ages took their names from the metals, Gold, Silver, Brass, and Iron, and the Hindu from the four throws of the Indian dice game, Krita, Tretā, Dvāpara, and Kali. These Yuga are combined to form a Maha Yuga or the Great Yuga.
In between any two yugas are intervening periods, known as sandhya and sandhyamshas. In some calculations, the period of sandhya and sandhyamshas are included within the period of Yuga and in some calculations, it is calculated separately for each Yuga, so the time period of Yuga may seem to differ in literature.
According to Hindu Mythology, the Maha Yuga lasted for 4,320,000 years. Kali-Yuga, which began on Friday, February 18, 3102 BC, will run for 432,000 years. Dvapara Yuga was strong with double the amount of moral substance as Kali Yuga had survived twice Kali Yuga, i.e., 864,000 years. Treta Yuga, provided with three of the four quarters of Dharma, has endured the length of three kali units, equivalent to 1,296,000 years. Krita (Satya) Yuga, the period of Dharma, has lasted for about 1,728,000 years. The grand total is thus 4,320,000 years, ten times the duration of one Kali Yuga.
| Yuga | Duration in Years |
| Satya (Krita) Yuga | 1,728,000 years |
| Tretā Yuga | 1,296,000 years |
| Dvapara Yuga | 864,000 years |
| Kali Yuga | 432,000 years |
| Maha Yuga | 4,320,000 years |
1. Satya (Krita) Yuga
Krita is the perfect participle of the verb kri, to do; it literally means “done, made, accomplished, perfect.” This is the dice throw that wins the jackpot, the total gain. According to the Indian conception, the idea of total, or totality, is associated with the number four. “Four square” signifies “totality.” Anything complete and self-contained is conceived as possessing all of its four “quarters” (pada). It is established firmly on its “four legs” (catuḥ-păda).
Krita (Satya) Yuga, the first of the ages, is the perfect yuga. Dharma, the world’s moral order (which is in virtual existence before the beginning but then becomes manifest in the world’s spheres, energies, and beings), was perfect during this period.
During this yuga, men and women are born virtuous. They devote their lives to the fulfillment of the duties and tasks divinely ordained by Dharma. The brahmins are established in saintliness. Kings and feudal chiefs act according to the ideals of truly royal conduct. The peasants and towns folk are devoted to husbandry and crafts. The lower, servile classes abide lawfully in submission. People even of the lowest extraction observe the holy order of life.
Total time period of Krita (Satya) Yuga
- Krita-yuga = 4000 divine years,
- Sandhya = 400 divine years,
- Sandhyansa = 400 divine years.
Total = 4800 divine years x 360 days = 1,728,000 human years.
One divine year is equivalent to Three hundred and sixty human years. You can find more about the measurement of time in Hindu mythology/culture in this blog post.
2. Tretā Yuga
As the life process of the world-organism gains momentum, however, order loses ground. Holy Dharma vanishes quarter by quarter while its converse gains the field.
Tretā is the triad or triplet; three of the quarters. Etymologically, the word is related to the Latin tres, Greek treis, and English three. During Tretā Yuga, the universal body, as well as the body of human society, is sustained by only three-fourths of its total virtue. The modes of life proper to the four castes have begun to lapse into decay. Duties are no longer the spontaneous laws of human action but have to be learned.
Total time period of Tretā Yuga
- Treta Yuga = 3000 divine years,
- Sandhya = 300 divine years,
- Sandhyansa = 300 divine years.
Total = 3600 divine years x 360 days = 1,296,300 human years.
3. Dvapara Yuga
Dvāpara Yuga is the age of the dangerous balance between imperfection and perfection, darkness and light. Its name is derived from dvi, dva, dvau, meaning “two” (compare the Latin duo, French Deux, English deuce, Greek dúo, Russian dva). During Dvāpara Yuga, only two of the four quarters of Dharma are still effective in the world; the others have been irrecoverably lost. Dvapara Yuga was described as surviving twice of Kali Yuga, i.e., 864,000 years.
Ethical order, instead of firmly standing on four legs, or resting safely on three, now balances on two. Destroyed is the ideal, semi-divine status of society. The knowledge of the revealed hierarchy of values has been lost. Perfection of the spiritual order failed to energize human and universal life.
All human beings, brahmins, kings, tradespeople, and servants are blinded by passion and eager for earthly possessions. People started to become averse to the fulfillment of sacred duties. True saintliness, to be achieved only through devotional observances, vows, fasting, and ascetic practices, becomes extinct.
Total time period of Dvapara Yuga
- Dvapara-yuga = 2000 divine years,
- Sandhya = 200 divine years,
- Sandhyansa = 200 divine years.
Total = 2400 divine years x 360 days = 864,000 human years.
4. Kali Yuga
Finally, Kali Yuga, the dark age, miserably subsists on twenty-five percent of the full strength of Dharma. Egoistic, devouring, blind, and reckless elements now are triumphant and rule the day. Kali means the worst of anything; also, “strife, quarrel, dissension, war, battle.”
During the Kali Yuga, man and his world are at their very worst. The moral and social degradation is characterized in a passage of the Vishnu Purāna: “When society reaches a stage, where property confers rank, wealth becomes the only source of virtue, passion the sole bond of union between husband and wife, falsehood the source of success in life, sex the only means of enjoyment, and when outer trappings are confused with inner religion …” then we are in the Kali Yuga, the world of today.
In the present cycle, this age is computed as having begun Friday, February 18, 3102 BC. Kali-yuga will last for 432,000 years.
The total time period of Kali Yuga
- Kali Yuga = 1000 divine years,
- Sandhya = 100 divine years,
- Sandhyansa = 100 divine years.
Total = 1200 divine years x 360 days = 432,000 human years.