In Jainism, it is believed that performing austerities (tapas), such as fasting (upavasa), helps to burn accumulated karma and can reduce future suffering, including that which may be experienced in the realms of hell (Naraka). However, Jain scriptures do not specify an exact number of years of hell that are reduced by performing a particular fast or austerity.

The impact of fasting and other penances depends on one's intention, sincerity, and the extent of austerity. These practices help in purifying the soul and reducing the intensity and duration of karmic consequences, but Jain texts like the Tattvartha Sutra and Uttaradhyayana Sutra emphasize that the results vary for each individual based on their karmic bondage.

In summary, Jainism teaches that fasting helps reduce the effects of negative karma and possibly shortens one's time in hell, but it does not provide a fixed calculation or number of years. The emphasis is on sincere practice and self-purification rather than quantifying the exact reduction in years of suffering.