Rahu Kalam Calculator

Rahu Kalam Calculator

Rahu Kalam is a period of roughly 90 minutes that occurs every day and is traditionally considered inauspicious for starting new activities - travel, ceremonies, signing contracts, or launching a business. Alongside it, Panchangam (Hindu almanac) tradition also tracks two other inauspicious windows, Yamagandam and Gulika Kalam, and one auspicious window, Abhijit Muhurat, which falls around midday and is considered favorable for important work.

This calculator works out the exact start and end time of all four periods for any day of the week, based on your local sunrise and sunset time.

How it's calculated

The daylight period (sunrise to sunset) is traditionally divided into 8 equal segments. Each of Rahu Kalam, Yamagandam, and Gulika Kalam always falls in a fixed segment number depending on the day of the week - this mapping has been used in Panchangam calculations for centuries and stays the same regardless of how long the day is.

$$segment\_length = \frac{sunset - sunrise}{8}$$ $$period\_start = sunrise + (segment\_number - 1) \times segment\_length$$ $$period\_end = period\_start + segment\_length$$

The segment number for each period depends on the weekday:

Day	Rahu Kalam	Yamagandam	Gulika Kalam
Sunday	8	5	7
Monday	2	4	6
Tuesday	7	3	5
Wednesday	5	2	4
Thursday	6	1	3
Friday	4	7	2
Saturday	3	6	1

Abhijit Muhurat is calculated differently - it's centered on solar noon (the midpoint between sunrise and sunset) and spans 1/15th of the daylight period, since the day is traditionally split into 15 equal muhurtas and Abhijit is the 8th, middle one.

$$solar\_noon = sunrise + \frac{sunset - sunrise}{2}$$ $$abhijit\_length = \frac{sunset - sunrise}{15}$$

How to use it

1. Pick the day of the week you want to check.
2. Enter the local sunrise time in 24-hour HH:MM format (e.g. 06:15).
3. Enter the local sunset time in the same format (e.g. 18:30).
4. Submit to see the Rahu Kalam window highlighted, plus a full table of all four periods with their start and end times.

Worked example

For a Monday with sunrise at 06:00 and sunset at 18:00, the daylight period is 12 hours (720 minutes), so each of the 8 segments is 90 minutes long. Monday's Rahu Kalam falls in segment 2, which starts 90 minutes after sunrise:

• Rahu Kalam: 7:30 AM - 9:00 AM
• Yamagandam (segment 4): 10:30 AM - 12:00 PM
• Gulika Kalam (segment 6): 1:30 PM - 3:00 PM
• Abhijit Muhurat (centered at 12:00 PM solar noon, 48 minutes wide): 11:36 AM - 12:24 PM

These times shift automatically if you enter a different sunrise/sunset (e.g. for your city and season) or pick a different weekday.