Lord Brahma is the first living entity and the secondary creator of this universe.  He possesses the longest duration of life in this universe.  In this article, let us deduce the life span of Lord Brahma in human years.

Srimad Bhagavatam says (3.11.12), “Two solar movements make one day and night of the demigods, and that combination of day and night is one complete calendar year for the human being”.

This means, 1 human year  =  1 day & 1 night of demigods

In Vedic calculations, 1 year = 360 days & nights.

Thus,

1 year of demigods  =  360 human years

Just like there are 7 days in a week and 12 months in a year, there are four yugas which repeat in cycles – Satya Yuga, Treta Yuga, Dvapara Yuga & Kali Yuga.

Srimad Bhagavatam further states (3.11.19), “The duration of the Satya millennium equals 4,800 years of the years of the demigods; the duration of the Treta millennium equals 3600 years of the demigods; the duration of the Dvapara millennium equals 2,400 years; and that of the Kali millennium is 1,200 years of the demigods.”

Thus,

Duration of Satya Yuga        =  4800 x 360 =  1,728,000 human years

Duration of Treta Yuga        =  3600 x  360 =  1,296,000 human years

Duration of Dwapara Yuga  =  2400 x 360  =     864,000 human years

Duration of Kali Yuga            =  1200 x 360  =     432,000 human years

Thus one yuga cycle                                       =  4,320,000 human years (4 million 320 thousand human years)

One yuga cycle is called as Maha-Yuga.

Srimad Bhagavatam says (3.11.23), “the four yugas multiplied by one thousand comprise one day on the planet of Brahma. A similar period comprises a night of Brahma, in which the creator of the universe goes to sleep.”

Thus,

Lord Brahma’s 1 day or 1 Kalpa  =  4,320,000 x  1000  =  4,320,000,000 human years (4 billion 320 million human years)

1 day of Brahma  +  1 night of Brahma  = 2 Kalpas  =  8,640,000,000 human years (8 billion 640 million human years)

Srimad Bhagavatam further states (3.11.33), “the process of the exhaustion of the duration of life exists for every one of the living beings, including Lord Brahma. One’s life endures for only one hundred years, in terms of the times in the different planets”.

It means, Lord Brahma’s Life Span  =  His 100 years

Thus, Lord Brahma’s Life Span in human years can be calculated as follows:

2 Kalpas  x  No. of days in a year  x  100

i.e. 8,640,000,000 x  360  x  100

which equals to 311,040,000,000,000

Thus, Lord Brahma’s life span is equal to 311 trillion 40 billion human years.  This period is called “Maha Kalpa”.

Srila Prabhupada says, “By these calculations the life of Brahma seems fantastic and interminable, but from the viewpoint of eternity it is as brief as a lightning flash. In the causal ocean there are innumerable Brahmas rising and disappearing like bubbles in the Atlantic. Brahma and his creation are all part of the material universe, and therefore they are in constant flux”.