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

Expressions researched:
"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"

Srimad-Bhagavatam

SB Canto 2

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 (BS 5.48)). 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.

SB 2.10.46, Translation and Purport

This process of creation and annihilation described in summary herein is the regulative principle during the duration of Brahmā's one day. It is also the regulative principle in the creation of mahat, in which the material nature is dispersed.

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 (BS 5.48)). 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.