You need to multiply your CGPA with 10 to get the percentage. So, percentage = CGPA*10. This method is only applicable to colleges affiliated with Anna University. You can find information regarding methods for the calculation of CGPA, on the backside of your university marksheet. There will be detailed info regarding credit letters and credit values.
The method of calculation of CGPA in Anna University is printed on the side of the mark sheet. If you want to find out the percentage, simply multiply your CGPA by 10.
There is, however, a drawback to the grade point average system. A student who has failed to achieve the minimum passing marks will not be able to know the same.
At the same time, if a student gets marks higher than 90, then their marks will be considered to be the centum score. The high scorer gets this advantage.