A monthly fixed rate mortgage payment never changes over the life of the loan. The interest rate is locked in at the beginning, so payments remain the same every month, allowing for predictable budgeting. Although the principal and interest portions of the payment change over time, the total monthly mortgage payment stays constant. However, if the mortgage includes escrow for property taxes and insurance, those portions may change annually, affecting the total payment but not the fixed principal and interest portion.
In summary, a fixed rate mortgage payment is characterized as never changing in terms of principal and interest amounts.