Hello Dear,

To convert CGPA into percentage, multiply the CGPA with 9.5 to get the overall indicative percentage. But if it is showing invalid you can contact to the college authority/ MHT CET authority regarding this. Hence every college have different multiplying factors. In some examination you can write total marks as 1000 and obtained marks as 613. If your CGPA is 6.13 out of 10. But you should confirm with the concerned authority. you can write mail or directly call to them.

Good Luck