The calculator must report the Tithi at Sunrise, as this determines the religious observance for that day. If a Tithi begins after sunrise and ends before the following sunrise, it is considered "lost" (Kshaya Tithi) for ritualistic purposes in some traditions, though astronomically valid.
Shukla Paksha (Bright Fortnight): This is the waxing phase of the moon, starting from the day after the new moon (Amavasya) and ending on the full moon (Purnima). It is generally considered an auspicious time for new beginnings and growth. tithi calculator
The calculator will then display the Tithi for that day. The calculator must report the Tithi at Sunrise,
Purnima: The full moon, a peak of lunar energy used for various major festivals like Holi or Raksha Bandhan. tithi calculator