"College credits" can mean either semester hours or quarter hours. If you're trying to convert from quarter hours to semester hours, it's basically a 3 for 2 relationship. See the conversion table attached.
The credits will equal the hours, so basically you just need to convert to semester hours if your school was still on quarter hours.
Well in our class schedule catalog at my community college says how many hours the class has. For example most of the 1 unit classes has 18 hours of class time. You need to see if its the same in your college. You need to find all the classes you have taken and add up the hours each class has. In my college catalog it has:
this is at least the majority of the classes, i haven't seen any other class that's had more or less hours for the amount of units it's offering unless if it has a lab like chemistry. i hope this helps.