Jain units of time
Jain units of time range from an infinitesimally small, indivisible measurement of time known as a samayā to innumerable lengths of time measured in sagaropama and palyopama years, including cycles of cosmic time that repeat general events in Jain cosmology. Each cycle is divided into two eras of equal duration described as the avasarpini and the utsarpini. The former is a descending era in which virtue gradually decreases. The latter is an ascending era in which the reverse takes place. The present era is stated to be the former.
Units
Division of the time cycle
| Ara | Start | Length |
| suṣama-suṣamā | 1 quadrillion sāgaropama years ago | 400 trillion sāgaropama |
| suṣamā | 600 trillion sāgaropama years ago | 300 trillion sāgaropama |
| suṣama-duṣamā | 300 trillion sāgaropama years ago | 200 trillion sāgaropama |
| duṣama-suṣamā | 100 trillion sāgaropama years ago | 100 trillion sāgaropama minus 42,000 years |
| duṣama | 525 BCE | 21,000 years |
| duṣama-duṣama | 20476 CE – 41476 CE | 21,000 years |
Note: In the utsarpiṇī, the six aras take place in reverse order.