Answer

In Jain Dharma, the Chaturth Kāl — the fourth era of the descending time cycle, called Duḥṣamā-Suṣamā Kāl — lasts for:

1 Koḍākoḍī Sāgaropam

Explanation

According to Jain cosmology, time moves in two half-cycles:

• Utsarpiṇī – ascending time cycle
• Avasarpiṇī – descending time cycle

Each half-cycle has six eras, called Ārās.

In the present Avasarpiṇī, the fourth era is called:

Duḥṣamā-Suṣamā

This was the era in which the 24 Tirthankars of the present Avasarpiṇī appeared, including Bhagwan Rishabhdev and Bhagwan Mahavir.

Its duration is:

1 Koḍākoḍī Sāgaropam

A Sāgaropam is an extremely vast Jain time unit, beyond ordinary human calculation.

Takeaway

Chaturth Kāl = Duḥṣamā-Suṣamā Kāl = 1 Koḍākoḍī Sāgaropam.