Tithi is the lunar day — the second limb of the panchanga. A tithi is the time it takes the Moon to gain 12° of separation from the Sun. There are 30 tithis in a lunar month, split into two pakshas (halves) of 15 each.
Shukla Paksha (waxing) and Krishna Paksha (waning)
The waxing fortnight runs from new moon to full moon; the waning fortnight from full moon to next new moon. The calculator labels each tithi with its paksha prefix:
- S.P. = Shukla Paksha (waxing) — 15 tithis ending at S.P. Purnima (full moon).
- K.P. = Krishna Paksha (waning) — 15 tithis ending at K.P. Amavasya (new moon).
Tithi classification by quality
| Group | Tithis | Quality |
|---|---|---|
| Nanda (joyful) | Pratipada, Shashthi, Ekadashi | Light celebrations, learning |
| Bhadra (prosperous) | Dwitiya, Saptami, Dwadashi | Auspicious — marriage, housewarming, vehicles |
| Jaya (victorious) | Tritiya, Ashtami, Trayodashi | Competitive work, legal matters |
| Rikta (empty) | Chaturthi, Navami, Chaturdashi | Avoid for auspicious starts |
| Purna (full) | Panchami, Dashami, Purnima, Amavasya | Mixed — Purnima good, Amavasya for ancestor work only |
How the filter works
By default all 30 tithis are allowed. Tighten it by selecting only the Bhadra + Jaya + Nanda tithis (and avoiding Rikta + Amavasya) for routine auspicious acts:
- Marriage / housewarming: S.P. Dwitiya, Tritiya, Panchami, Saptami, Dashami, Ekadashi, Dwadashi, Trayodashi; K.P. Dwitiya, Tritiya, Panchami.
- Avoid: Chaturthi, Navami, Chaturdashi (rikta), Amavasya.
- Shukla Paksha is generally preferred over Krishna Paksha for auspicious work.