Brahmi muhurta is a very auspicious time for yoga, Suryanamaskara, meditation and pranayama. In this time the human body and mind gets great energy.
To calculate Brahmi Muhurta subtract 96 minutes from sunrise to begin. Duration of Brahmi Muhurta is 48 minutes.
For example: Let's say the sunrise time is 06:06 AM. Subtract 96 minutes to arrive at 4:30 AM. This would to determine the start of Brahmi Muhurta. Duration of Brahmi Muhurta is 48 minutes. Hence the Brahmi muhurta time will be 04:30 AM to 05:18 AM.