In Jainism, there is no single fixed number of days for fasting. The length and type of fasting depend on your vows (vrata) and tradition (Digambar or Shwetambar), as well as the purpose of the fast. Here are the common patterns for lay practitioners:

• Upvas (one-day fast): Many Jains fast for one day, often refraining from food after sunrise until the next sunrise, or eating only one meal for the day.
• Partial or restricted fast: Some fast by avoiding certain foods (like grains, or sweets) or by eating only one meal (ekasan) or by fasting for only part of the day.
• Multi-day fasting: During festival periods like Paryushan or Das Lakshana, some choose to fast for several days in a row (2, 4, 8 days, or longer) with varying strictness (complete fast vs. partial fast).
• Ascetic/rigorous fasts: Jain monks and nuns may undertake longer and stricter fasts (including complete fasts with very limited or no food or water) under strict guidance.

If you’re new to fasting, start with a modest practice (like one day of vow-based abstention or eating only one meal) and gradually learn from a Jain teacher or community about the specific rules that apply to your tradition.