There are three different types of creation, called mahā-kalpa, vikalpa and kalpa. In the mahā-kalpa the Lord assumes the first puruṣa incarnation as Kāraṇodakaśāyī Viṣṇu 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 Kāraṇodakaśāyī Viṣṇu are called mahā-kalpa. The creation of Brahmā and dispersion of the material ingredients are called vikalpa, and the creation by Brahmā in each day of his life is called kalpa. Therefore each day of Brahmā is called a kalpa, and there are thirty kalpas in terms of Brahmā’s days. This is also confirmed in the Bhagavad-gītā (8.17) as follows:

sahasra-yuga-paryantam ahar yad brahmaṇo viduḥ rātriṁ yuga-sahasrāntāṁ te ’ho-rātra-vido janāḥ

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 one thousand divya-yugas make one day of Brahmā. The creation during the day of Brahmā is called kalpa, and the creation of Brahmā is called vikalpa. When vikalpas are made possible by the breathing of Mahā-Viṣṇu, this is called a mahā-kalpa. There are regular and systematic cycles of these mahā-kalpas, vikalpas and kalpas. In answer to Mahārāja Parīkṣit’s question about them, Śukadeva Gosvāmī answered in the Prabhāsa-khaṇḍa of the Skanda Purāṇa. They are as follows:

prathamaḥ śveta-kalpaś ca dvitīyo nīla-lohitaḥ vāmadevas tṛtīyas tu tato gāthāntaro ’paraḥ

rauravaḥ pañcamaḥ proktaḥ ṣaṣṭhaḥ prāṇa iti smṛtaḥ saptamo ’tha bṛhat-kalpaḥ kandarpo ’ṣṭama ucyate

sadyotha navamaḥ kalpa īśāno daśamaḥ smṛtaḥ dhyāna ekādaśaḥ proktas tathā sārasvato ’paraḥ

trayodaśa udānas tu garuḍo ’tha caturdaśaḥ kaurmaḥ pañcadaśo jñeyaḥ paurṇamāsī prajāpateḥ

ṣoḍaśo nārasiṁhas tu samādhis tu tato ’paraḥ āgneyo viṣṇujaḥ sauraḥ soma-kalpas tato ’paraḥ

dvāviṁśo bhāvanaḥ proktaḥ supumān iti cāparaḥ vaikuṇṭhaś cārṣṭiṣas tadvad valī-kalpas tato ’paraḥ

saptaviṁśo ’tha vairājo gaurī-kalpas tathāparaḥ māheśvaras tathā proktas tripuro yatra ghātitaḥ pitṛ-kalpas tathā cānte yaḥ kuhūr brahmaṇaḥ smṛtā

Therefore the thirty kalpas of Brahmā are: (1) Śveta-kalpa, (2) Nīlalohita, (3) Vāmadeva, (4) Gāthāntara, (5) Raurava, (6) Prāṇa, (7) Bṛhat-kalpa, (8) Kandarpa, (9) Sadyotha, (10) Īśāna, (11) Dhyāna, (12) Sārasvata, (13) Udāna, (14) Garuḍa, (15) Kaurma, (16) Nārasiṁha, (17) Samādhi, (18) Āgneya, (19) Viṣṇuja, (20) Saura, (21) Soma-kalpa, (22) Bhāvana, (23) Supuma, (24) Vaikuṇṭha, (25) Arciṣa, (26) Valī-kalpa, (27) Vairāja, (28) Gaurī-kalpa, (29) Māheśvara, (30) Paitṛ-kalpa.

These are Brahmā’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 Mahā-Viṣṇu, as stated in the Brahma-saṁhitā ( yasyaika-niśvasita-kālam athāvalambya jīvanti loma-vilajā jagadaṇḍa-nāthāḥ ). The Brahmās live only during the breathing period of Mahā-Viṣṇu. So the exhaling and inhaling of Viṣṇu are mahā-kalpas, and all these are due to the Supreme Personality of Godhead, for no one else is the master of all creations.