What is Choghadiya? The Vedic Daily Timing System, Explained for Developers

The question behind every Indian calendar app

If you've built software for the Indian market — or used any Indian calendar, wedding planner, or panchang app — you've encountered Choghadiya. It's the system that tells you which parts of the day are favorable and which are not, based on a repeating planetary cycle tied to the weekday and the actual sunrise and sunset at your location.

Choghadiya (Sanskrit: "good quarter") divides each solar day into 8 equal slots from sunrise to sunset, and each solar night into 8 equal slots from sunset to the next sunrise. Each slot is ruled by one of 7 planetary qualities, cycling in a fixed order that changes its starting point based on the weekday.

Hundreds of millions of people across South Asia consult Choghadiya before signing contracts, starting journeys, scheduling ceremonies, or beginning any work they consider important. It is one of the most practically used elements of the Vedic Panchanga system.

The 7 qualities

Each Choghadiya slot carries one of seven qualities, each associated with a classical planet:

| Quality | Planet | Classical Assessment | Typical Use | |---------|--------|---------------------|-------------| | Amrit | Moon | Most auspicious | All favorable activities | | Shubh | Jupiter | Auspicious | Marriage, wealth, blessings | | Labh | Mercury | Profitable | Business, learning, financial activity | | Char | Venus | Good for movement | Travel, change, dynamic activities | | Udveg | Sun | Mediocre | Government work, acts requiring courage | | Kaal | Saturn | Inauspicious | Avoid starting important work | | Rog | Mars | Inauspicious | Associated with conflict and illness; avoid |

The qualities cycle in a fixed order: Udveg, Char, Labh, Amrit, Kaal, Shubh, Rog — then repeat. The starting quality for each day depends on the weekday's ruling planet. Sunday (ruled by the Sun) starts with Udveg. Monday (Moon) starts with Amrit. Tuesday (Mars) starts with Rog. And so on.

Night Choghadiya follows the same cycle but with a different starting point per weekday, also derived from classical tables (DrikPanchang standard).

Why sunrise matters — and why most implementations get it wrong

Choghadiya slots are not fixed clock times. They are proportional divisions of the actual solar day. A day slot on a summer solstice in Delhi (sunrise 5:23 AM, sunset 7:22 PM) is roughly 105 minutes long. The same slot on a winter solstice (sunrise 7:10 AM, sunset 5:29 PM) is roughly 77 minutes long.

This means any Choghadiya calculation that uses hardcoded sunrise times (like "6:00 AM") is wrong by definition. The error can exceed 90 minutes at high latitudes during summer or winter extremes.

Shubh Time uses the NOAA Solar Calculator algorithm to compute sunrise and sunset from first principles — Julian Day conversion, solar declination, equation of time, and hour angle calculation with standard atmospheric refraction correction (90.833 zenith). The result is accurate to within 1-2 minutes for latitudes between -72 and +72.

For polar regions where the sun doesn't set (polar day) or doesn't rise (polar night), the algorithm falls back to approximate values (4:00/20:00 and 6:00/18:00 UTC respectively) rather than failing silently.

Rahu Kaal, Gulika Kaal, and Yamaganda

Beyond the 8 Choghadiya slots, the Vedic daily timing system identifies three specific inauspicious windows within the solar day:

Rahu Kaal — The period ruled by Rahu (the north lunar node). This is the most widely observed inauspicious window across South Asia. The specific slot changes by weekday: Sunday it falls in the 2nd part of the day, Monday the 8th, and so on through a fixed weekly rotation.

Gulika Kaal — The period associated with Gulika (a sub-planet of Saturn). Less commonly observed than Rahu Kaal, but still checked for important initiations.

Yamaganda — The period associated with Yama (the lord of death in Vedic cosmology). Considered inauspicious for starting new ventures.

Each of these is exactly one-eighth of the solar day (sunrise to sunset), occupying a specific slot that rotates by weekday. Like Choghadiya, they require actual sunrise/sunset computation — not clock-time approximations.

Shubh Time computes all three windows using the same NOAA sunrise/sunset data as the Choghadiya calculation, ensuring consistency across the entire daily timing system.

The API

Shubh Time exposes three Choghadiya endpoints:

GET /v1/choghadiya — Returns 8 day slots and 8 night slots for a given date and location.

GET /v1/choghadiya?date=2026-03-29&lat=18.9667&lon=72.8333&tz=Asia/Kolkata

Each slot includes:

• quality — one of: amrit, shubh, labh, char, udveg, kaal, rog
• period — day or night
• isAuspicious — boolean
• planet — ruling planet name
• start / end — ISO 8601 timestamps
• description — classical meaning

GET /v1/rahu-kaal — Returns the three inauspicious windows (Rahu Kaal, Gulika Kaal, Yamaganda) for a given date and location.

GET /v1/daily-timings — Combined endpoint returning both Choghadiya slots and inauspicious windows in a single call. Results are cached in Redis for 24 hours, keyed by date + coordinates.

All endpoints require:

• date — YYYY-MM-DD (local date at the target location)
• lat — Latitude (-90 to 90, north positive)
• lon — Longitude (-180 to 180, east positive)
• tz — IANA timezone identifier (e.g., "Asia/Kolkata")

Authentication: Open access in alpha (no keys needed, rate-limited 100 req/hr/IP). Bearer token auth coming in beta. Full docs at /docs (Swagger/OpenAPI).

Use cases for developers

Calendar and scheduling apps — Show Choghadiya quality alongside time slots. Let users filter for auspicious windows when booking events.

Wedding and event planning platforms — Choghadiya is one of the first things checked when scheduling a ceremony. Integrate the API to show favorable time slots within a selected date.

Daily panchang apps — The /v1/daily-timings endpoint provides a complete daily view in a single cached call. Build a full panchang display without computing anything client-side.

Notification services — Query upcoming Amrit or Shubh periods and send push notifications: "Amrit Choghadiya begins in 15 minutes."

Travel planning tools — Char (Venus) Choghadiya is classically recommended for starting journeys. Surface this alongside departure time selection.

What Choghadiya is not

Choghadiya is a time-quality classification system, not a prediction framework. It does not forecast what will happen during any given period. It classifies periods according to a planetary rulership cycle that the Vedic tradition considers meaningful for timing decisions.

Whether you treat these classifications as practical guidance or cultural context, the underlying system is well-defined, deterministic, and computationally straightforward. The same inputs always produce the same output. There is no interpretation layer, no subjective scoring, and no hidden methodology.

The algorithm and its source data (DrikPanchang standard weekday tables) are open source and inspectable in the Shubh Time repository.