Why did my fixed payment amount increase when the interest rate went up?

A loan's fixed payment is generally set to the lowest amount possible to allow them to be paid off within the required time frame based on the terms of the repayment plan that you selected for repayment of your loan(s). A rise in the interest rate may make it impossible for a loan to be paid off in this required time frame based on the current fixed payment amount. Therefore in some instances, your fixed payment must be increased at the same time the interest rate increases to insure that the loan is fully repaid in the required time frame.