how is it possible for my IBR to be $0 per month for 240 months?

Okay so i have used numerous amounts of calculators based on my $8000 AGI (i guessed at it bc i have yet to receive my W2 form. They have all told me that my IBR would be in $0 to $0 payments per month for 240 or 300 months....but I am having trouble understanding how my payments can be $0 and my loan ends up paid off...? Do they pay for it? or is it just forgiven after that certain amount of months? If anyone has an idea of how it can be paid off if im not paying on it please shoot me an answer. thanks in advance <3

.x2015-01-12T02:27:23Z

When you are on the IBR plan you have to send documentation if your income every year, if your income changes then your payment amount will change too. So it may go up from $0 in the future?

But basically if you never make enough to pay off the loans completely then after 20-25 years the remainder of your loan is forgiven by the government. The exact time period for forgiveness varies depending on when you took out the loans, I think older loans have a 25 yr period and newer ones from like the past few years are forgiven after 20 yrs.