yugas

Yugas are a system of cyclical epochs in Hindu cosmology that describe successive ages through which the world passes. They form part of larger time cycles, notably the mahayuga, and are described in several scriptures, especially the Puranas. The four ages are traditionally listed in order of decreasing length and virtue: Satya Yuga (also called Krita Yuga), Treta Yuga, Dvapara Yuga, and Kali Yuga.

In common calculations, a mahayuga lasts 4,320,000 years, divided as follows: Satya Yuga 1,728,000 years; Treta Yuga 1,296,000 years; Dvapara Yuga 864,000 years; Kali Yuga 432,000 years. Each successive age is shorter and characterized by a decline in dharma, or moral order. The level of righteousness is said to be 100% in Satya Yuga, 75% in Treta, 50% in Dvapara, and 25% in Kali.

The cycle is circular: after Kali Yuga ends, a new Satya Yuga begins, completing a mahayuga, and the process repeats. In the broader cosmology, mahayugas occur within the day of Brahma, with 1,000 mahayugas making up a Brahma day, and Brahma living for 100 years. These scales emphasize cyclical time and the recurrent rise and fall of cosmic virtue.

Notes on interpretation vary among texts, and historical calendars differ in exact figures. Nevertheless, the framework of four sequential ages with diminishing duration and virtue serves as a common, neutral description across many Hindu traditions.