How long is a single Kalpa?

A single kalpa is as long as 1,000 cycles of four yugas which is equivalent to 4.32 billion years it's a day of Brahma.

A kalpa is a method used to indicate a period of time. It is a thousand cycle of 4 Yugas which are Satya yuga, Tretan yuga, Dvapara yuga and the Kali yuga. The satya is proposed to be virtue, wisdom and religion those yuga lasted 1,728,000 years.

The Tretan yuga lasted 1,296,000 years. The Dvapara yuga is a greater decrease in virtue and religion, it lasted 864,000 years and lastly the Kali yuga, which is the yuga we are now experiencing has been since 5,000 years.

1000 cycles of the four yugas-a kalpa is equal to 4.32 billion years and is a day of lord brahma. one thousand cycles of the four yugas (satya, treta, dvapara and the present kali yuga) or ages (gold, silver, bronze and iron age) equals to one kalpa. nrsimha appeared close to the end of satya yuga or the golden age. nrsimha, unlike many other incarnations does not appear one thousand times in one kalpa but around 10 times only. one kalpa equals to one day or night of lord brahma and only in the day of lord brahma that life in this material creation exists. with the onset of lord brahmas night, the entire universe is devastated and plunged into darkness. when another day of lord brahma begins, life again becoms manifest. every time nrsimha appears the pastime of nrsimha varies.