DIVYAVARṢA(M) 365 days make one year for human beings. One year for human beings is one day for the gods. 365 such days of the gods make one year for the gods. This means that 365 years for human beings are equal to one year for the gods. The year for the gods is known as “Divyavarsa” or “Divyavatsara”. Kṛtayuga is made up of 4,800 Divyavatsaras. Tretāyuuga has 3,600 Divyavatsaras. 2,400 Divyavatsaras make up one Dvāparayuga. Kaliyuga has 1,200 Divyavatsaras. 12,000 Divyavarṣas of this kind make up one “caturyuga”. 71 Caturyugas are the period of one Manu. After the end of the period of one Manu, the gods complete their term of existence. The total period of 14 Manus is called a Kalpa. At the end of every Kalpa there is a deluge. One Kalpa is one day time for Brahmā. After the deluge, until the time of one Kalpa, is Brahmā's night. There is no universe at that time. At the end of that Kalpa, the next Kalpa begins and Brahmā starts his work of creation. In this way when 360 days and nights of Brahmā are completed, it is one Brahmā Varṣa. One Brahmā life-span is 120 such years. After that there is nothing for a Brahmā's life-span. Then Brahmā is re-born and resumes creation.
[Bhāgavata, Daśama Skandha] .