“Upvās” in Jain Dharma means a full fast from sunrise to next sunrise.

• Shwetāmbara practice: boiled water only in daylight hours.
• Digambara practice: generally stricter—boiled water in fixed day-time windows; none at night.

“16 upvās” can be done:

• Consecutively (16 days in a row), or
• Non‑consecutively (e.g., on key tithis like 8th and 14th of each lunar fortnight until you complete 16), or
• Lined up with festivals: Shwetāmbara Paryushan (8 days) plus days before/after to total 16, or Digambara Daśalakṣaṇ (10 days) plus additional days to total 16.

Exact calendar dates depend on:

• Your tradition (Digambara or Shwetāmbara),
• Your city/time‑zone (tithi timings shift by location),
• Whether you want them consecutive or spread out.

Share your tradition, city, and whether you want 16 consecutive days or 16 selected tithis, and I will list the upcoming Gregorian dates accordingly. For basics on fasting types and discipline, see this brief guide