There are 7 Choghariya during day and 7 during night. They  are Shubh, Amrit, Chanchal, Rog, Kal, Labh, Udveg . Out of these seven  Shubh, Amrit and Labh are auspicious. Roughly their duration is 4 Ghati (approximately 1hr 36 min) each.
To know exact  time of the Choghariya take the duration of the day from Sun rise to Sun set and devide it  by 8.Keep adding this time duration from Sun rise time. So we will get the duration of each Choghariya. Like wise to know the Choghariya of night take the duration from Sun set to Sun rise and devide it by 8.Their sequence is different daily.For that you can refer the given chart on right.