A kalpa is an infinitely long series of world ages, each one being 2000 mahâyugas.
A mahâyuga is 360 normal yugas. Every few hundred years at the beginning, and a few hundred years at the end of such a period, comes what we would call the twilight of the gods.
At present, we are in the Kâli yuga. We have a bad prognosis.
Now the majority of people lie, there remain only a few who can bear the truth.
In the first yuga, everyone spoke the truth, in the second and the third ever fewer. ~Carl Jung, Psychology of Yoga and Meditation, Page 35
A yuga consists of 4800, 3600, 2400, and 1200 years.178 These 12,000 years179 × 360 are 1 mahâyuga and that is already 4.3 million years.180 A kalpa however is 2000 × 4.32 million.
That is 8.64 million years. And now one must work off his sinful deeds over the course of many million kalpas. ~Carl Jung, Psychology of Yoga and Meditation, Page 35