Purnima

A tithi is the time the Moon takes to gain 12° elongation from the Sun. Because lunar speed varies through the orbit, a tithi can be shorter or longer than 24 hours — sometimes one tithi spans portions of two solar days, and sometimes two tithis fall within a single solar day. The current tithi at sunrise is what determines the panchang for that day in most regional traditions.

The 30 tithis of the lunar month divide into two pakṣas of 15 each: śukla (the waxing fortnight, Pratipadā to Pūrṇimā) and kṛṣṇa (the waning fortnight, Pratipadā to Amāvāsyā). Purnima is the 15th tithi of the waxing fortnight — counted #15 in the canonical 30-tithi cycle.

Purna tithis (5, 10, 15) are the “full” tithis — ideal for completion-oriented work, the conclusion of long-running projects, and consummating ceremonies.

In Hindu life the tithi is one of the five limbs of the pañcāṅga (along with vāra, nakṣatra, yoga, and karaṇa). Together these five give the calendar its rhythm — determining muhūrta (auspicious time), vrata (fasting day), festival dates, and the daily cycle of pūjā. Reading the tithi correctly is foundational to traditional Hindu observance.

Many devotees take a vow to fast on a specific tithi every month — Ekādaśī (Vaiṣṇavas), Pradoṣa-Trayodaśī (Śaivas), Saṅkaṣṭī-Caturthī (Gaṇeśa devotees), Pūrṇimā (universal), or Amāvāsyā (ancestor rites). The merit of these vratas is described in the Purāṇas, especially the Padma, Skanda, and Bhaviṣya Purāṇas.

Modern panchangs published in major Indian languages (Drik, Lahiri, Kāśī Vidyāpīṭha Saṃvat) calculate the start and end times of each tithi for any given location. You can see the live tithi for your city on our daily Pañcāṅga.