Choutha kaal ya Dusamā-susamā kālā (Ārā) Avasarpini ke antargat chautha arā hai. Is arā ki lambi lambaai ke baare me Jain śāstr ke anusar:

• Naam: Dusamā-susamā (Dukhama-sukhamā)
• Lambaai: 1 kotikotī sagaropama saagaropama varg (ek bahut bada kāl), lekin isme se 42,000 varsh ghata diye jaate hain. Sankshipt roop me, yeh arā lagbhag 1 kotikotī sagaropama varsh minus 42,000 varsh ke barabar hota hai. Is arā ki shuruaat me logon ki ayu, shakti, aur dharma me sthiti bahut upar hoti hai, par samay ke sath kam hoti hai. ( jainknowledge.com)

• Vishist dharohar: Digambar aur Śvetāmbara dono mil kar is arā ko samanya roop se samajhte hain; dono tradition is arā ko samjhane me same chizo par zor deti hain, bas kuch historical tari qui farq mil sakta hai. (Current kal ki sthiti par dono mil kar is baat par sahamat hain ki hum abhi is Avasarpini ke 5th arā (Dusamā) me hain.) ( jainknowledge.com)

Agar aap chahen to main is arā ke baki 5 arā ki tulna ya unki visheshtaen bhi saral roop se samjha sakta/sakti hoon.