Grade Point Average, GPA
The GPA is a system of judging a student's performance and is followed throughout the United States.
If a student seeking admission to graduate studies has grades in a different system he/she should clearly mention that GPA system does not exist and provide details on the system.
In event of a system different form the usual GPA system, some universities may ask for a detail method of evaluation of the scores with respect to their scales. In such case consult the Registrar or the controller of examination of the University for an official evaluation to be included along with the transcripts. It is recommended to send your rank certificate/official average score of class/toppers grades etc to ease difference between GPA and your system.
US GPA System
Please note: There are grades in between too..
Try to make table of your University system and GPA system. Show the comparison between GPA and your System and get it sealed with University registrar and send it along with transcripts.
You can also use print of below URLs.
More info on GPA Conversion
University of California Berkeley
The University of Auckland
GPA Conversion : Simon Fraser University, Canada
Most US universities have a minimum Undergraduate GPA requirement of at least 3/4 for admission to graduate program. Minimum requirement for PhD is much more than 3/4. But evaluation of GPA might vary for international students. Also GPA is not the only criteria for admission we have seen students getting admission in top universities with low GPA.