A Tithi calculator is a digital tool—typically an app or online utility—that computes the exact lunar phase based on the Sun-Moon relationship.

Wi-Fi and cellular networks fail. Planes have airplane mode. Remote pilgrimage sites (like Tirumala, Kedarnath, or Rameswaram) often have patchy signals. A portable calculator works 100% offline.

This astronomical complexity creates a perennial problem: When exactly does Ekadashi start? On which Gregorian date does Amavasya fall this year? Enter a quiet but transformative tool: the .