Panchanga

A free, offline-first Hindu calendar that runs entirely in your browser.

🌎 panchang.surendrajat.xyz

No accounts. No ads. No tracking. Install once, works on a plane.

Features

• Daily panchanga — Tithi, Nakshatra, Yoga, Karana with end times; Vara anchored to sunrise at your location.
• Lunar month — Masa with Adhik Maas detection; Amanta and Purnimanta conventions.
• Muhurtas — Brahma Muhurta, Abhijit, Vijaya, Godhuli, Nishita Kaal, and inauspicious windows (Rahu Kaal, Yamaganda, Gulika).
• Festivals — Pan-India set with rules aligned to Drik Panchang (Pradosha, Aparahna Nishita, Bhadra-aware dates, Sankranti sunset cutoff).
• Year context — Vikram Samvat, Shaka Samvat, Kaliyuga, Ritu, Ayana.
• Sun & Moon — sunrise, sunset, moonrise, moonset, moon phase with illumination %.

Languages

• English and हिन्दी (auto-detected from your system language on first launch).
• Numerals in Latin (1, 2, 3) or Devanagari (१, २, ३).

Locations

Bundled city list covers India's metros, Hindu-diaspora centres in Southeast Asia, the Gulf, the Caribbean, Mauritius, Fiji, and major Western cities. GPS is also supported — everything is computed locally for the true local sunrise.

Calculations

• Ephemeris: astronomy-engine — apparent geocentric Sun/Moon, sub-arcsecond accuracy.
• Ayanamsa: Lahiri (Chitra Paksha) by default; KP, Raman, Yukteshwar, True Chitra available.
• Sunrise: Upper limb with atmospheric refraction, matching the Drik default.
• Full methodology and tiebreaker rules: METHODOLOGY.md.

Privacy

Everything lives in your browser's IndexedDB. There is no server, no telemetry. Source files are precached by the service worker so the app loads instantly and works offline.

Run locally

pnpm install
pnpm dev        # http://localhost:5173
pnpm test       # unit + regression suite
pnpm build      # static output → ./dist

Requires Node 24 and pnpm 11 (pinned in .nvmrc).

Contributing

Bug reports, accuracy comparisons against local panchangas, and language translations are welcome. See CONTRIBUTING.md.

License

Copyright 2026 @surendrajat

This project is licensed under the AGPL-3.0-or-later.

Acknowledgements

• astronomy-engine — ephemeris calculations.
• Festival rules verified against drikpanchang.com.