Rahu Kaal Calculator

Rahu Kaal — also spelled Rahu Kalam, Rahu Kala or Rahu Kalaam — is one of the most widely observed timings in the Hindu Panchang (the traditional Vedic almanac). It is a single 1/8th portion of the daytime, the period from sunrise to sunset, that is regarded as inauspicious for beginning anything important. The name comes from Rahu, one of the nine celestial influences (Navagraha) in Vedic astrology. This calculator finds the exact Rahu Kaal window for any Indian city and date, shows all eight daylight portions so you can see where it falls, and lays out the weekday pattern that decides which portion is affected.

The tool is intended for anyone who follows the tradition and wants a quick, location-aware answer — families planning a griha pravesh or wedding muhurat, business owners choosing when to open a new venture or sign a contract, travellers picking a departure time, or simply someone curious about the practice. Within the tradition, people typically avoid starting new work, important purchases, journeys, and auspicious ceremonies during this window, while routine activities already in progress are considered unaffected.

How is Rahu Kaal computed?

The calculation has two clear steps. First, the calculator works out sunrise and sunset for your exact latitude, longitude and date using standard astronomy (the NOAA solar-position method). Second, it divides the daylight period — sunrise to sunset — into eight equal portions. Rahu Kaal is always exactly one of those eighths; which one is fixed by the day of the week, following long-established Vedic convention: Monday = 2nd portion, Tuesday = 7th, Wednesday = 5th, Thursday = 6th, Friday = 4th, Saturday = 3rd, and Sunday = 8th. The portions are always counted forward from sunrise.

Worked example

Suppose sunrise is at 6:00 AM and sunset at 6:00 PM, giving 12 hours of daylight. Dividing by eight makes each portion 90 minutes long. On a Tuesday — when Rahu Kaal is the 7th portion — you count six full portions of 90 minutes (nine hours) from sunrise, which lands at 3:00 PM, and the window runs to the end of the seventh portion at 4:30 PM. So Rahu Kaal that day would be 3:00 PM to 4:30 PM. On a Monday with the same sunrise and sunset, the 2nd portion runs from 7:30 AM to 9:00 AM instead.

Why does the clock time shift?

Two things move the window. The length of daylight changes through the year — longer in June, shorter in December — so each one-eighth portion grows or shrinks with the season. And clock sunrise itself shifts with longitude, arriving earlier in eastern cities like Kolkata and later in western cities like Mumbai. As a result Rahu Kaal's clock time changes from day to day even on the same weekday, and differs from city to city even on the same date. That is exactly why entering your specific city (or custom coordinates) and date matters rather than relying on a single fixed timetable.

Tips, accuracy and a respectful note

Always choose the city closest to where you actually are, or switch to Custom and enter precise coordinates, so the sunrise and sunset — and therefore the window — match your location. The sunrise/sunset values here are accurate to within about ±2-3 minutes, which is ample for everyday planning. For a binding muhurat for a marriage or a major religious ritual, treat this as a helpful first reference and confirm with a qualified Panchang authority who applies full Drik Ganita with nutation corrections. Rahu Kaal is a sincere cultural and religious belief held by many; this calculator is offered respectfully and for informational purposes — there is no scientific claim that activities begun during this window have different outcomes, and whether to observe it is entirely a personal choice.