Applying for a PhD in Europe as a South American. Do i convert all my grades to GPA or ECTS scale I'm applying for a PhD position in Europe. I'm from South America and our grading system is quite different. As a requirement i need to send a transcript. Do i need to convert all my grades to GPA or ECTS? (Also, do you have any useful information on how to do it?) 

Thank you.
Actually, the institution you apply to normally does this themselves from official transcripts that you have sent from your earlier education: undergraduate, masters, ...

Depending on the program you apply to some courses will be more important than others, and the receiving institution knows what they are looking for. When necessary, they will discuss the grading system with the other institutions as needed. 

Schools around the world are quite good at this, actually.