* If you take 15 credits per semester: It will take you 2 semesters (or one academic year).
* If you take 12 credits per semester: It will take you 2.5 semesters (a little over one academic year).
* If you take fewer credits per term: It will take you longer.
Therefore, you need 30 more credits to complete your degree. The time frame is dependent on your course load.