Rahu Kaal: What It Is and How It's Calculated

What is Rahu Kaal?

Rahu Kaal (राहु काल) is a roughly 90-minute period that occurs once every day, ruled by Rahu, the shadow planet that Vedic astrology associates with confusion, obstacles, and illusion. Unlike most astrological concepts that depend on someone's birth chart, Rahu Kaal applies to everyone, everywhere, on a given day. It moves to a different part of the day depending on the weekday, and its exact clock time shifts slightly every single day because it's anchored to sunrise and sunset, not the clock.

Where the name comes from

In Vedic mythology, Rahu is the severed head of the demon Svarbhanu, who drank the gods' nectar of immortality and was decapitated by Vishnu before he could swallow it. The head, now immortal, chases the Sun and Moon across the sky out of vengeance, and occasionally catches them, which Vedic tradition offers as the explanation for solar and lunar eclipses. Rahu has no body, so it's described as a shadow or node rather than a physical planet, specifically the point where the Moon's orbit crosses the ecliptic going north. That node moves slowly through the zodiac, but Rahu Kaal itself is a separate, simpler daily calculation unrelated to that slow zodiacal motion.

How the calculation actually works

Take the time between sunrise and sunset on a given day and divide it into eight equal parts. Each part is ruled by one of the seven classical planets, in a fixed sequence, with one planet repeating since there are eight slots and only seven planets. Rahu always rules a specific numbered slot depending on the day of the week, never the same slot two days running. That's why Rahu Kaal lands in the late afternoon on Sundays, the morning on Mondays, and somewhere different again on every other day.

Because the calculation starts from actual sunrise and sunset, Rahu Kaal's clock time drifts through the year. In summer, when days are longer, each of the eight parts is longer too, so Rahu Kaal can run closer to 100 minutes. In winter it can shrink to under 80. This is also why Rahu Kaal differs by location: two cities at different longitudes have different sunrise times, so the same calendar date can have Rahu Kaal start at slightly different clock times in each city.

*Approximate, for a sunrise/sunset close to 6:00 am / 6:00 pm. Actual timing shifts with the season and your location. See today's exact Rahu Kaal →

What people avoid during Rahu Kaal

The tradition isn't that Rahu Kaal is unlucky for everything, it's specifically considered a poor window for starting something new: signing a contract, launching a business, beginning a journey, scheduling a wedding ceremony, or undergoing elective surgery. Routine, ongoing activities, eating, working, attending meetings that were already scheduled, aren't affected. The underlying logic is about beginnings specifically, not the period as a whole.

Rahu Kaal vs Yamaganda vs Gulika Kaal

All three are calculated the same way, by dividing daylight into eight parts, and all three are considered inauspicious. The difference is which planet rules which slot: Rahu Kaal follows Rahu's slot, Yamaganda follows the slot associated with Yama, the god of death, and Gulika Kaal follows a slot tied to Saturn's shadow son. Of the three, Rahu Kaal is the one most widely checked day to day, largely because it's the one most consistently mentioned across regional Panchang traditions.

Frequently asked questions