If you took out a loan of 5000 for a total of 4 years, it would all depend on the type of loan you took out to pay it back. A government subsidized loan will take out an amount of interest/APR. But, all of these interests you have to pay back more than double the cost of what you took out. A non-subsidized loan you have to pay it back while you are still in school or the interest will add up over time. A credit union loan is much more flexible and easier than the others as you can take as much money as needed with a set plan for payment. You have to wait till after 6 months of your graduation to pay back your loans. One way to reduce the interest is to pay them early. The APR on a student loan is 3.25%. The formula is A=P(1+r/n)^nt.