<prompt> Human: I read this all the time, but I confess I dont quite understand it forgive me; Im new! The money I pay on my student loans 3.19 and 4.275 is just going away forever, as far as I can tell. Ill never see it again. So how is it the equivalent of investing in funds with 3.19 and 4.275 rates of return? It seems to me that Great Lakes is the one getting that rate of return, not me. Beyond eventually out of debt, what do I get out of this that makes the above statement true?Apologies if this is a baby question; Im new to the PF scene and, regrettably, I have no math.  <response>: If your student loan were 100 with the rate of 3.19, then youd have to pay 3.19 in interest. If you paid off that loan, then you dont have to pay the interest on that in the future, so you saved yourself 3.19. You could invest your 100 into a fund, and you might make back 5, or 5. Or you might make less or even lose money. Meanwhile, youd still have to pay that 3.19 in interest because you didnt pay off your loan. If you just used that money to pay off the loan, you are guaranteed to save the money you would have had to pay in interest. You got a guaranteed 3.19 return on your money versus putting it into a fund. 