There are three different types of creation, called

1. maha-kalpa,
2. vikalpa and
3. kalpa.

In the maha-kalpa the Lord assumes the first purusa incarnation as Karanodakasayi Visnu with all the potencies of the mahat-tattva and the sixteen principles of creative matter and instruments. The creative instruments are eleven, the ingredients are five, and all of them are products of mahat, or materialistic ego. These creations by the Lord in His feature of Karanodakasayi Visnu are called maha-kalpa.

The creation of Brahma and dispersion of the material ingredients are called vikalpa, and

the creation by Brahma in each day of his life is called kalpa. Therefore each day of Brahma is called a kalpa, and there are thirty kalpas in terms of Brahma's days.

This is also confirmed in the Bhagavad-gita (8.17) as follows:

sahasra-yuga-paryantam

ahar yad brahmano vidu

hratim yuga-sahasrantam

te 'ho-ratra-vido janah

In the upper planetary system the duration of one complete day and night is equal to one complete year of this earth. This is accepted even by the modern scientist and attested by the astronauts. Similarly, in the region of still higher planetary systems the duration of day and night is still greater than in the heavenly planets.

The four yugas are calculated in terms of the heavenly calendars and accordingly are twelve thousand years in terms of the heavenly planets. This is called a divya-yuga, and onethousand divya-yugas make one day of Brahma. The creation during the day of Brahma is called kalpa, and the creation of Brahma is called vikalpa. When vikalpas are made possible by the breathing of Maha-visnu, this is called a maha-kalpa. There are regular and systematic cycles of these maha-kalpas, vikalpas and kalpas. In answer to Maharaja Pariksit's question about them, Sukadeva Gosvami answered in the Prabhasa-khanda of the Skanda Purana.

Therefore the thirty kalpas of Brahma are:

(1) Sveta-kalpa,

(2) Nilalohita,

(3) Vamadeva,

(4) Gathantara,

(5) Raurava,

(6) Prana,

(7) Brhat-kalpa, (8) Kandarpa,

(9) Sadyotha,

(10) Isana,

(11) Dhyana,

(12) Sarasvata,

(13) Udana,

(14) Garuda,

(15) Kaurma,

(16) Narasimha,

(17) Samadhi,

(18) Agneya,

(19) Visnuja,

(20) Saura,

(21) Soma-kalpa,

(22) Bhavana,

(23) Supuma,

(24) Vaikuntha,

(25) Arcisa,

(26) Vali-kalpa,

(27) Vairaja,

(28) Gauri-kalpa,

(29) Mahesvara,

(30) Paitr-kalpa.

These are Brahma's days only, and he has to live months and years up to one hundred, so we can just imagine how many creations there are in kalpas only. Then again there are vikalpas, which are generated by the breathing of Maha-visnu, as stated in the Brahma-samhita (yasyaika-nisvasita-kalam athavalambya jivanti loma-vilaja jagadanda-nathah [Bs. 5.48]). The Brahmas live only during the breathing period of Maha-visnu. So the exhaling and inhaling of Visnu are maha-kalpas, and all these are due to the Supreme Personality of Godhead, for no one else is the master of all creations.