A variable interest rate, also known as a variable or adaptable rate, applies to any type of debt such as loans, bonds, mortgages or loans that do not have a fixed rate over the term of the instrument.  The mortgage interest rate setting period begins with the interest rate setting period or a fixed mortgage, but the borrower may exercise the option of taking a lower interest rate when interest rates fall. The option to get the lowest price usually expires within 30 to 60 days. In contrast, a variable rate convertible mortgage (MRA) allows the borrower to benefit from lower interest rates for a few years before being converted into a fixed mortgage. Some types of variable-rate loans, especially mortgages, may have other peculiarities, such as.B. interest rate ceilings or restrictions on the maximum interest rate or the maximum change in the permitted interest rate. Suppose a borrower blocks a rate of 5%.