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Rahu Kalam Calculator

Rahu Kalam is a daily period, roughly 90 minutes long, classically ruled by the shadow-planet Rahu and traditionally avoided for starting new, important undertakings — travel, signing contracts, or opening a new venture. It falls in one specific eighth of the daylight hours, and exactly which eighth depends on the day of the week. This calculator computes its precise start and end time for any date and place.

Day divided into 8 equal periods (sunrise to sunset) · Fixed classical weekday-to-segment mapping (e.g. Monday = 2nd eighth, Saturday = 3rd eighth)

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James Whitfield

Reviewers

Sarah Mitchell, M.A. in Cultural Astronomy & Astrology and Marcus Reynolds, Professional Astrologer & Astronomer

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What Is Rahu Kalam?

The daylight span from sunrise to sunset is classically divided into 8 equal segments, and a fixed segment is assigned to Rahu's rulership on each weekday — for instance, the 2nd eighth on Monday, the 7th on Tuesday, and so on through the week. During this window, tradition advises against starting new ventures, though ongoing activities and routine tasks are not typically discouraged.

Why It Changes by Weekday, Not by Date

Unlike planetary transits or dasha periods, Rahu Kalam's segment assignment is fixed to the 7-day weekly cycle rather than to any specific astronomical position of Rahu itself — meaning the SEGMENT NUMBER stays the same for a given weekday year-round, while the actual CLOCK TIME shifts daily along with sunrise and sunset.

How Rahu Kalam Is Typically Applied

Most practitioners treat Rahu Kalam as a caution specifically for BEGINNING something new, not as a blanket restriction on all activity during that window — a meeting already in progress, for example, is not typically considered problematic to continue through it.

Rahu Kalam Calculator FAQs

What is Rahu Kalam?
A daily period, roughly 1.5 hours long, falling in a fixed eighth of the daylight hours (which eighth depends on the weekday), classically ruled by Rahu and traditionally avoided for starting new important activities.
Does Rahu Kalam fall at the same clock time every day?
No — while its position within the day (which of the 8 daylight eighths) stays fixed for a given weekday, the actual clock time shifts daily along with that day's sunrise and sunset times.
Should I avoid all activity during Rahu Kalam?
Traditional guidance specifically cautions against STARTING new, important undertakings during this window — ongoing activities and routine daily tasks are not typically considered problematic.
Is Rahu Kalam the same as Yamagandam?
No — they are separate inauspicious windows with their own distinct weekday-to-segment mapping, so they fall at different times of day and are traditionally read for slightly different concerns.
Why does this calculator need my exact location?
Because Rahu Kalam's clock time is derived directly from that day's sunrise and sunset, both of which vary meaningfully by location — the same weekday segment falls at a different clock time in different cities.

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